Women's Physical Health After Childbirth: Do Violence and Depression Histories Represent Risk Factors for More Postpartum Physical Health Symptoms?

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WOMEN'S PHYSICAL HEALTH AFTER CHILDBIRTH: DO VIOLENCE AND DEPRESSION HISTORIES REPRESENT RISK FACTORS FOR MORE POSTPARTUM PHYSICAL HEALTH SYMPTOMS?

Donna Lynn Ansara

A thesis submitted in conformity with the requirements for the degree of Masters of Science Graduate Department of Health Administration University of Toronto

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Women's physical health after childbirth: Do violence and depression histories represent risk factors for more postpartum physical health symptoms?

Donna Lynn Ansara, Masters of Science, 2001 Graduate Department of Eealth Administration, University of Toronto

A prevalence study was conducted to document the extent and the correlates of cornrnon postpartum physical health symptoms, and to determine whether violence and depression histones were associated with these symptoms. Women were recruited in the hospital after delivery and were interviewed by telephone 8 to 10 weeks later. Data were also obtained fiom women's medical records. Two hundred of the 332 (60.2%) women who were approached completed the study. Most women (96%) reported at least one physical symptom. The nsk factors identified by the stepwise logistic regression were: assisted vaginal delivery @ = 2.04;

95% -CI = 1.26 - 3.29), sick leave during pregnancy (RR = 1.92; 95% -CI = 1.1 1 - 3.33), depression during pregnancy (R.J = 2.0 1 ;95% -CI = 1.20 - 3.38), and possibly adult emotional abuse (RR = 1.57; 95% -CI = 0.97 - 2.56). Postnatal physical symptoms are common. Practice implications for health professionals are discussed. 1 would sincerely like to thank my cornmittee members for their guidance and contribution to this thesis. Dr. Marsha Cohen who supervised this project, providing invaluable mentorship and support throughout and for encouraging the timely completion of this thesis. Dr. Ruth Gallop for providing thought-provoking feedback on the framing of the thesis and Dr. Rose Kung for contributing her obstetrical expertise.

1 am also gratefbl to Dr. Marsha Cohen and Dr. Heather Maclean for providing fhding support, space, and cornputer availability through the Centre for Research in Women's Health. 1 would also like to thank the research staff who worked on this project.

Finally, 1 am indebted to the women who generously volunteered their time to participate in this study and who shared many of their difficult personal expenences. TABLE OF CONTENTS

.. ABSTRACT ...... II ... ACKNOWLEDGEMENTS ...... 111 TABLE OF CONTENTS...... iv LIST OF TABLES ...... v LIST OF APPENDICES ...... vi INTRODUCTION ...... 1 1.1 Smdy rationale ...... 1 STUDY OBJECTIVES ...... 4 BACKGROUND ...... -5 2.1 Critique of medical understanding of materna1 health ...... 5 2.2 Theoretical hmework for the present shidy ...... 8 2.3 Epidemiology of postpamim materna1 physical symptoms ...... 9 2.4 Studies of specific postpartum matemal physical syrnptoms ...... 13 2.5 Violence and health ...... 17 2.6 Depression and health ...... 29 2.7 Other factors...... -35 2.8 Literature review of instruments used in the smdy ...... 39 2.9 Surnrnary ...... 43 METHODS ...... -44 3.1 Study design ...... 44 3.2 Study setting ...... -44 3.3 Participantsr .' ...... -45 3.4 Procedure ...... , ...... 47 3.5 Instruments...... 49 3.6 Research ethics and participant confidentiality ...... 36 3.7 Statistical Method ...... 59 RESULTS ...... -80 4.1 Response rates ...... 80 4.2 Characteristics of the study participants ...... 82 4.3 Cornparison of respondents and non-respondents ...... 82 4.4 Cornparison of the respondents to the population...... 84 4.5 Statistical Analysis ...... 85 DISCUSSION ...... 98 5.1 Summary and interpretation of the findings ...... 98 5.2 Methodological issues ...... 107 5.3 Strengths and limitations of the smdy ...... 10 5.4 Implications of the study findings ...... 112 5.5 Directions for fbture research ...... 115 FOOTNOTES ...... 118 REFERENCES ...... 119 TABLES ...... 135 APPENDICES ...... 161 LIST OF TABLES

Table I Characteristics of the Study Participants ...... 136 Table II Cornparison of Respondents and Nonrespondents ...... 138 Table III Construct Validity of the Outcome Variable ...... 141 Table IV Number of Postpartum Somatic Symptoms...... 142 Table V Prevalence of Postpartum Somatic Symptoms ...... 143 Table VI Prevalence of a History of Violence ...... 144 Table VLI Prevalence of a History of Depression ...... 145 Table VIII Bivariate Analysis: Sociodemographic Predictor Variables ...... 146 Tables IX Bivariate Analysis: Psychosocial Predictor Variables ...... 147 Table X Bivariate Analysis: Health Care-Related Factors. Including Matemal and Obstetric Predictor Variables ...... 149 Table XI Bivariate Analysis: History of Violence Predictor Variables ...... 151 Table XII Relationship between Adult Emotional Abuse and Other Physical and Sexual Abuse Types ...... 152 Table Xm Relationship between the New Adult Emotional Abuse Variables and Postpartum Somatic Symptoms ...... 153 Table XTV Multicollinearity Analysis ...... 154 Table XV List of Predictor Variables for the Multivariate Logistic Regression Mode1 ...... 155 Table XVI Multivariate Analysis: Regression Diagnostics ...... 156 Table XVII Multivariate Analysis: Parameter Estimates fiotn the Univariate and Multivariate Logistic Regression Models ...... 157 Table XVIII Relative Odds and Relative Risks of Postpartum Somatic Symptoms ...... 158 Table XIX Relative Odds of Postpartum Somatic Symptoms: Multivariate Model Derived Excluding Antenatal Depression as a Potential Covariate...... 159 Table XX Relationship between Postpartum Depression and Postpartum Somatic Symptoms ...... 160 Appendix A Information Package for Potential Participants ...... 162 Appendix B Consent Fom ...... 165 Appendix C Ethics Approval ...... -167 INTRODUCTION

1.1 Study rationûle

Postpartum matemal health has long been a neglected area of empirical investigation (Graham

& Campbell, 1992; Kline et al., 1998). Studies documenting women's health expenences following childbirth have only recently emerged in the medical and epidemiologic literature. A surge of recent publications on women's mental health afier childbirth have helped to elucidate the pervasiveness, nature, and determinants of postpartum depression, postpartum bIues, and puerperal psychoses (e.g., Campbell & Cohn, 1991 ; Cooper & Murray, 1995; Cooper et al.,

1996; Cor et al., 1987; Cox et al., 1993; Fergusson et al., 1996; Kendell et al., 1987; O'Hara et al., 1990; Schaper et al., 1994; Zelkowitz & Milet, 1995; Righetti-Veltema et al., 1998).

With respect to studying women'sphysicaf health after childbirth, the prominent outcome variable within the literature has been matemal mortality (Graham & Campbell, 1992).

Consequently, the focus of much research has been on examinhg rare, severe, and potentially life-threatening obstetric complications that arise during pregnancy, delivery, and the puerperiurn

(i.e., the six-week pend following delivery assumed to be required for complete physiologie recovery to pre-pregnancy state) (Graham & Campbell, 1992). Examples of such problems include postpartum hemorrhage, eclampsia, deep venous thrombosis, and pulmonary emboiism.

Relatively little is loiown however, about the extent and correlates of less senous (and possibly more prevalent) physical health symptoms that are rneaningfd to women following childbirth. The relevance and timeliness of research focussing on these more common matemal healtb symptoms was underscored in a recent study by Kline and colleagues (1998). They convened a series of focus groups of new mothers and obstetrician clinicians (midwives, family practitioners, obstetncians, and gynecologists) to determine women-centred materna1 health outcomes for research. These outcomes represent indicators of health that are considered to be important to mothers. During the sessions, mothers were asked to discuss how pregnancy and childbirth had affected their health. Clinicians were asked to discuss what they considered were important matemal health outcomes. An interesting fïnding reported in the study was that both mother and clinician groups admitted that they did not know what constituted 'typical' postpartum recovery and expressed dissatisfaction with the paucity of available information conceming women's postpartum health. Four categories of outcomes were identified: psychological, physical, and sexual postpamim health, and social and role demands.

With respect to the physical and sexual sequelae of childbirth (the health outcomes relevant for the present study), a large proportion of women (exact nurnber not indicated in article) reported experiencing various health symptoms (e.g., pain, discomfort, fatigue, dyspareunia, decreased libido). However, the women felt that the information provided to them by their caregivers about their health, particularly about what to expect during the postpamim period, was inadequate. They felt unprepared for the health changes and problems that they encountered dwing this time. At the sarne time, clinicians lamented that a lack of scientific information about these matemal health outcomes hindered their ability to adequately counsel women.

In this shidy, we also wished to identiQ possible risk factors for these symptoms. Many studies have exarnined health-care related, obstetrical, or medical risk factors within this population of women (e.g., length of stay, mode of delivery, or perineal trauma). However, few studies have examined the manner in which psychosocial factors are related to women's postnatal physical well-being, and to our knowledge, no studies have specifically examined women's histories of violence and depression. Thus, the aim of the study was to document the extent of some of the under-recognized, but more comrnon physical health symptoms that are expenenced by women following childbirth.

We also attempted to identify some of the nsk factors for these symptoms. The two main factors that we exarnined were a history of violence and a history of depression. Other factors that we exarnined were sociodemographic factors, other psychosocial factors, and health care-related factors. STUDY OBJECTIVES

1. To determine whether a history of violence (sexual, physical, or emotional) experienced in

childhood, adulthood, or both, is associated with more postparhim matemal physical health

symptoms

2. To determine whether a history of depression is associated with more postpartum matemal

physical health symptoms

3. To identify any other risk factors for postpartum materna1 physical health symptoms

including:

Sociodemographic factors

Ps yc hosocial factors

Health care-related factors, including matemal and obstetrical factors BACKGROUND

2.1 Critique of medical understanding of matemal health

The foifowing section provides a critique of the current body of knowledge on postpartum

materna1 hea fth within the medical fiterature. The conceptual framework used for the presenr

study is also described.

The manner in which researchers have studied, constructed, and organized our understanding

of matemal health has largely been guided by the medical model (Oakley, 1980). Medicalization

"refers to the way in which the jurisdiction of modem medicine has expanded in recent years and

now encompasses many problems that formerly were not defined as medical entities" (Gabe &

Calnan, 1989, p. 223). Many scholars have written extensively and critically on the powerful role

that the medicaI model has played in claiming and pathologizing the normal experiences of

women's lives, particularly those pertaining to reproductive processes such as pregnancy and

childbirth (e.g., Oakley, 1980, 1984).

Under the medical model, pregnancy is treated as a 'diseased state' and childbirth most ofien

occurs in hospitals (Scott & Niven, 1996). In most industrialized societies, pregnancy is actively

managed by medical practitioners with routine prenatal care and with the widespread use of

medical technologies to screen for serious matemal health problems and fetal congenital anomalies (Oakley, 1980; Scott & Niven, 1996). The intense medical monitoring and swveillance of women during pregnancy, and the relative inattention given to women's postpartum health suggests that materna1 health has conventionally been conceptualized as a discrete, time-lirnited, biological experience (Graham & Campbell, 1992). Several researchers have noted the relative lack of clinical and research attention given to wornen's postnatal health 5 (e.g., Glazener, 1997a).

Evidence of this biological and time-limited conceptualization of pregnancy is demonstrated by the narrow definition of pregnancy outcomes as the avoidance of matemal or pe~atal mortality (Graham & Campbell, 1992; Oakley, 1980). Hence, much of the research has focused on severe and life-threatening obstetrical complications occurring during labour, childbirth, or the puerperium (Graham & Campbell, 1992). Other indicators of matemal health and morbidity, such as positive or optimum functioning, degree of discornfort or dissatisfaction, and presence of disability or other health problems have typically not been given serious research attention

(Graham & Campbell, 1992).

2.1.1 Medical Mode1

This focus on the physical dimensions of health along witb medicine's increasing ability to use technologies to observe and diagnose physical health problems (i.e., the 'clinical gaze'), rather than relying on patients' descriptions of their own health, represents the fmt value assumption of the biomedical model; mind-body dualisrn (Freund & McGuue, 1999). Physical health and morbidity are assumed to fùnction independently fkom psychological, affective, or other cognitive and behavioral processes.

A related tenet of the medical model; physical reductionism, also assumes illness to be located within the physical body. Other forms of illness such as psychological, behavioral, or social have long been excluded from the biomedical discourse (Freund & McGuire, 1999).

Physical reductionisrn also characterizes the supremacy that is ascribed to the biological determinants of health over psychological, emotional, social, political, or economic factors

(Freund and McGuire, 1999). The doctrine of speciific etiology assumes that illness is caused by specific pathogens, which

can be directly manipulated by clinicians to bring about a 'cure' for the disease. This assurnption

has been critiqued on the grounds that although it rnay have worked well in explaining the

causation of infectious diseases, it performs poorly when addressing cbronic illnesses (Freund &

McGuire, 1999). This traditional medical approach also lacks power in explaining and addressing

models of health that include the broader social, political, or economic deteminants of health for

which no "magic-bullet" of a cure exists (Clarke, 2000).

Finally, the machine metaphor describes the modem practice of allopathic medicine of cornpartmentalizing health and treating the different organs and systems of the body as discrete entities that are isolated and independent fiom the rest of the body. For instance, the development of obstetrics and gynecology as a medical specialty to deal with pregnancy and matemal health defmes this experience as a discrete and time-limited event in a woman's life. Within this paradigm, the factors deemed relevant in affecting matemal health are those limited to biological and obstetrical factors associated with pregnancy.

2.1.2 Implications of a medical understanding of postpartum matemal health

The consequence of studying women's health within the narrow confines of the biomedical perspective is that it generates a limited mode1 of health by decontextualizing women's lives

(Gijsbers Van Wijk et al., 1996). Decontextualization describes the process whereby theonsts abstract fiom real experiences to derive a monolithic or generalized representation of experience

(Thiele, 1986). Eichler (1997) describes decontextualization as a form of sexist or gender- insensitive research, whereby gender is ignored as a socially important variable in the investigation of issues where it is highly relevant. Introducing context into the study of women's health would acknowledge the significance of gender as a mediator of people's life experiences

and their health. As an exarnple, studying matemal health in its social context would

acknowledge the pervasiveness of violence against women in society and the profound impact

that it bas on women's health.

Thiele (1986) asserts that reducing reproduction to a biological event is a form of sexist

scholarship that she refers to as nafuralism. Theonzing fkom this stance has profound political

implications in that "what is 'natural' ceases to require a social or political explanation. .. it

becomes incapable of generating social change" (Thiele, 1986, p. 36). Decontextualization and

naturalism therefore may hinder out ability to accurately understand and consequently improve

women's postpartum health. With respect to ignoring gender violence as an issue in its own right

in medical practice and research, these theoretical moorings illustrate how the continuation of

violence against women is sustained by failing to recognize and challenge this personal, social,

and political problem.

2 -2 Theoretical ftamework for the present study

Gijsbers Van Wij k and colleagues (1 996) challenge a purely medical understanding of

women's health and describe a more holistic and gender-sensitive approach to women-centred

health care and research. The central tenet of this model emphasizes that health and illness

should be viewed in their social context. Specifically, they propose a model of health that is

influenced by a broad array of factors including individual level physical, psychological, and

social factors, and by societal level factors such as inequality and power (Gijsbers Van Wijk et al., 1996).

In a discussion paper on the relationship between measurement-related factors and the neglect of matemal health programs, research, and policy, Graham and Campbell (1992) also reinforce the importance of redefining heaith and its antecedents in a more comprehensive and contextually sensitive manner. By evaluating the broader antecedents, matemal health becomes defined as more than just a medical issue (Graham & Campbell, 1992). Furthemore, they posit that a more inclusive model should assume a "life-cycle approach", which emphasizes the continuity between a woman's life experiences and her curent health status. This model would challenge the notion of pregnancy as a time-limited event, and maternal health as being strictly affected by factors directly related to the process of childbearing. Factors that occurred years earlier (e.g., history of violence and depression), even in childhood, would be legitimate and necessary to examine.

This exploratory study represents an attempt to build a more comprehensive model of women's postnatal health, first by documenting the extent of some of the less severe physical health problems experienced by women 8 to 10 weeks after childbirth. Secondly, the study examines a broad array of potential risk factors that are relevant to women's lives and identifies those that are associated with an increased risk of postparturn maternal physical health symptoms.

2.3 Epiderniology of postpartum materna! physical symptoms

This literature review describes four comprehensive studies that emined the prevalence and correlates of a varieîy of postpartuum health symptoms in women. Studies that focussed on single posrparfum health problems will also be reviewed.

MacArthur et al., (1991) conducted the first comprehensive sîudy of long-terni postnatal health problems. The sample represented 1 1,7O 1 women who gave birth at one hospital in Birmingham between 1978 and 1985. The authors assessed postpamim symptoms retrospectively

(between 13 months and 9 years after delivery) using a postal questionnaire. The outcomes of interest were newly onset health problems (i.e., those that were not experienced durùig or pnor to the pregnancy of interest) occuning within the first 3 postpartum months and lasting more than 6 weeks.

The data revealed that 47% of the women reported experiencing at least one such postpartum health problem. Backache was the most cornmonly reported symptom (14%), followed by extreme tiredness (12.2%), musculoskeletal symptoms such as neck-ache, shoulder ache, pain and weakness in the limbs, and tingling in the hands and feet (8.2%), headaches (3.6%), and migraines (1.4%). The findings of the study also underscored the chronic nature of many of these problems. The authors reported that most (exact number not indicated) of these symptoms lasted more than one year and approximately two-thirds were still present at time of the inquiry

(between 13 months and 9 years postpartum). Unresolved symptoms such as stress incontinence, urinary fiequency, and hemorrhoids were reported by 10.6%, 4.4%, and 5.3% of the women respectively. Despite the chronic nature of these problems, many of the women had not sought help fiom a doctor.

Gjerdingen et al. (1993) conducted a prospective study of white, married, employed (or employed during pregnancy), nulliparous women who were surveyed at 1,3,6,9, and 12 months postpartum. Postal surveys were used to collect information on postpartum symptoms and the number of illness days experienced within the previous 2 weeks. An illness day was defuied as either having had to reduce one's activities as a result of health problems or reduced energy, or continuing with one's tasks despite having felt ill. For many of the symptoms examined, prevalence was highest at one month postpartum. Breast problems including discornfort, infection, and nipple irritation were reported by approximately half of the sample at one month

postpartum. Other symptoms that were frequently reported at one month were fatigue (43%),

hemorrhoids (-27%), poor appetite (-20%), constipation (- 18%), increased sweating (47%),

acne (-16%), hand numbness or tingling (-1 l%), dizziness (-2 l), hotfiashes (-IO%), and

vaginal discomfort (-10%). The mean number of illness âays that were reported during the 2-

week interval preceding the inquiry was also greatest at one month postpartum (3.9 days),

ranging Erom an average of 1.6 to 1.9 days thereafter.

Glazener et al. (1995) prospectiveIy surveyed a 20% random sarnple of al1 women who

delivered during a one-year period in a region of Scotland. The sarnple was stratified by place of

postnatal care. Postal questionnaires were sent to 139 1 women one week, 8 weeks, and 12 to 18

months after delivery. The survey listed a series of health symptoms and participants were asked

to check those that they had experienced during each survey interval. Participants also listed any other symptoms that were not listed.

During the first postpartum week (while still in hospital), the majority of women (85%) reported having had at least one health problem. Afier hospital discharge until8 weeks postpartum, approximately the sarne proportion (87%) reported at least one problem, and between 8 weeks and 18 months postpartum, fully 76% reported one or more symptoms. The mean nurnber of symptoms indicated for each of these intervals was 2.3,2.5, and 1.8 respectively. Commonly reported symptoms for each of the study intervals were: tiredness (42%,

59%, 54%), painfùl penneum (42%, 22%, IO%), problems breastfeeding (33%, 28%, 12%), backache (22%, 24%, 20%), constipation (19%, 20%, 7%), piles (17%,23%, 15%), anemia

(15%, 25%, 7%), headache (14%, 22%, 15%), high blood pressure (9%,3%, 1%), and vaginal discharge (696, 15%,8%). Other symptoms such as abnormal bleeding, urinary tract infeîtion, and stitches breaking down were also reported by some of the women.

Brown and Lumley (1998) conducted a cross-sectional survey in which they assessed the

extent of various health problems six to seven months after delivery. A postal questionnaire was

sent to al1 women who gave birth within a two-week penod in Victoria, Australia. Postpartum

symptorns were ascertained retrospectively using a self-report checklist. The authors found that

an overwhelming 94% of the women reported experiencing at least one health symptom after

delivery until the time of the study. The types of problems reported were tiredness (69.4%), pain

fiom the caesarian wound (60.7%), backache (43.5%)- sexual problems (26.3%), hemorrhoids

(24.6%)- painfùl perineum (2 1.O%), and mastitis (1 9.6%), bowel problems (1 2.6%), more coughs

or col& than usual(11.6%), and urinary incontinence (10.7%). The authors reported that just

under three-quarters of the women who expenenced a health problem consulted a health

professional. In line witb the findings of Kline et al. (1998)- half of these women wished that

they had received more help or advice about their health dunng this penod.

A comparison of the findings of these studies reveal that significantly fewer women in the

MacArthur et al. study reported at least one health problem (47%) relative to women in the

Glazener et al. (85%, 87%- 76%) and Brown and Lumley (94%) studies. This finding may have partially been a function of the longer recall period used in the MacArthur et al. study (13 months to 9 years). Participants may not have recalled having had certain problems or may have recovered fiom them and therefore minimized their importance. Also- MacArthur et al. specifically set out to ascertain incident cases of long-terni problems and used strict criteria regarding their onset and duration. These were symptoms that had occurred within 3 postparturn months and that lasted greater than 6 weeks. The other two studies assessed the prevalence of health problems without stipulating time constraints on their onset or duration. 2.4 Studies of specific postpartum matemal physical syrnptoms

2.4.1 Postpartum perineal discornfort

Abraham et al. (1990) conducted a prospective study in which they investigated the time in which nulliparous women with vaginal deliveries ceased to feel penneal discomfort. In the study, almost al1 women (96%) experienced some fom of perinea1 damage. The median time reported by women of feeling no discomfort during regular activities such as walking and sitting was one month. However, 12% of women required more than 2 months to recover. With respect to level of penneal discomfort during sexual intercourse, women typically reported longer recovery periods (3 months), and 1 I % of women required more than 6 months.

2.4.2 Postpartum sexual health

Robson et al. (198 1) demonstrated a marked reduction in the frequency and enjoyment of sexual activity in nulliparous women in the 3 months following delivery compared to their pre- pregnancy levels. At three months postpartum, 40% of the women in the study reported unresolved pe~ealdiscomfort, soreness, dyspareunia, and decreased libido due to tiredness.

Glazener (199%) found that by 8 weeks postpamim, 25% of women had not attempted intercourse. For those who did, the median time interval between delivery and trying or resuming intercourse was 5 weeks, and 90% of the women had resumed by 10 weeks. Arnongst those who had attempted intercourse within the first two months, 43% reported expenencing at least one problem and 16% had two or more problems. The most comrnonly reported symptoms were perineal pain (28.1%), tiredness (20.7%), and decreased interest (8.7%). The authors also demonstrated the enduring nature of many of these problems; approximately half of al1 women reported symptoms between 2 and 18 months postparturn. This is approximately the same proportion that reported symptoms within the first 2 months.

Barrett et al. (1999) studied a sample of nulliparous women and found that by 7 to 8 weeks postpartum, only 58% had resumed intercourse. This proportion rose to 88% by 7 months postpartum. During the fmt three postpartum months dyspareunia was reported by 58% of women, loss of sexual desire by 44%, and vaginal dryness by 39%. These problems were significantly more common during the 3 months after childbuth than pnor to the pregnancy; 22% of women reported experiencing dyspareunia at some point before becoming pregnant, 13% reported a loss of sexual desire, and 24% reported vaginal dryness.

2.4.3 Postpartum pain

Russell et al. (1993) determined the extent of various health problems, including long term backache in nulliparous women and their association with epidural analgesia. Participants had given birth in one year at a London hospital. Information about postparturn symptoms was collected using a postal questionnaire sent to women 12 to 15 months after delivery. Telephone interviews were conducted with women who did not respond to the mail swey. The study fond that during the postnatal year, 64% of women reported at least one postpartum health problem, and 46.9% of them had persistent syrnptoms lasting more than 6 months. Backache was the most prevalent problem at 29.5%, and 15.4% of these were incident cases (Le., no backache reported during pregnancy). The prevalence and incidence proportions for the other health problems were: neckache and shoulder pain (9.2%, 5.7%), headache (7.8%, 3.7%), abdominal pain (6.6%, 4.9%). 2.4.4 Postpartum incontinence

Viktmp et al. (1992) documented the extent of postpartum stress (urinary) incontinence in nulliparous women. They found that 7% of women had a new onset of symptoms in the year following childbirth. About one quarter of these women (24%) still had unresolved symptoms at the completion of the study (1 year postpartum). This contrasts with the rapid resolution of symptoms in women who had developed incontinence during their pregnancy; only 3% still had symptoms at 1 year meauthors attributed the persistent nature of new postpartum incontinence to obstetric factors during delivery.

MacArthur et al. (1 997) conducted a prevalence study in which they ascertained the extent and severity of postpartum faecal incontinence. Interviews were conducted an average of 10 months postpartum. Three problems were assessed: 1) frank incontinence, which was described as "no waming that she needed to go", 2) soiling or staining of her underwear, and 3) urgency,

"felt the need to go but couldn't hold on". The proportion of women reporting one or more symptoms was 6.1%, and 4% of these were incident cases (i.e., no problems were present prior to delivery). Fifty-eight percent of women who experienced incontinence indicated that symptoms began either irnmediately, or within the first 2 weeks following delivery. The mean duration of symptoms was 6 months, and by the time of the interview 6 1% of the women still had unresolved symptoms. Daily symptoms were reported by 39% of women, and 36% reported symptoms on some days of every week.

2.4.5 Postpartum mastitis

Mastitis is an infection of the breast that occurs in lactating women. Symptoms include swelling, redness, breast pain, and flu-like symptoms such as a fever, body aches, nausea, and vomi~g.Treatment usually includes antibiotics and women usually can continue breastfeedhg

(Kaufmann & Foxman, 1991; Kinlay et al., 1998).

Kaufinann and Foxman (1991) conducted a historical cohort study in which they ascertained the incidence of mastitis in a group of lactating women who had sought prenatal care and had delivered at a Michigan hospital within a 2-year period. Participants were asked to remto the hospital's obsteûics and gynecology clinic for their 6-week postpartum check-up. The outcome variable was a clinical diagnosis of mastitis noted in women's medical records. Using these data, the authors estimated the risk of mastitis within the fïrst seven postpartum weeks to be 2.9%.

Kinlay et al. (1998) conducted a prospective cohort study of lactating women who had delivered at one of two hospitals located in New South Wales within the span of 6 months. Postal questionnaires were sent to participants to assess the presence of mastitis using specific symptom criteria. Within the first 6 postpartum months, 20% of the women met the study criteria for mastitis.

This estimated 20% nsk is significantly greater than the 2.9% reported by Kaufmann and

Foxman (1 991 ), but is almost identical to that found by Brown and Lumley ( 1998) (19.6%; study descnbed earlier in chapter). Kinlay et al. suggest that this difference may be due to the fact that the Kauhann and Foxman relied on women presenting at the hospital clinic, whereas women are actually more likely to consult their general practitioner for this problem. It is not likely that this difference can be attributed to the different time intervals used in both studies (7-weeks versus 6 months). Mastitis typically has an early onset; thus it is unlikely that the Kaufinann and

Foxman study underestimated the risk because of the shorter postpartum interval that was used.

In fact, Kinlay et al. found that 75% of the women who developed mastitis did so within the ht

7 weeks. 2.5 Violence and health

2.5.1 History of violence (smdy objective #l)

in a review paper by Bohn and Holz (1996), they outline six dimensions of health that have

been show to be negatively affected by a histoiy of violence and abuse: 1) physical or medical,

2) somatic, 3) psychological or emotional, 4) social or interpersonal, 5) behavioral or sexual, and

6) pregnancy-related effects. The psychological sequelae of violence are perhaps the best

understood. Symptoms of depression, pst-traumatic stress disorder, anxiety, and fear are

described as cornmon reactions to interpersonal muma. More recently, researchers have begun to

explore the physical sequelae of violence. The following sections review some of the available

literature in this area.

2.5.1.1 Definition of violence

Violence has generally been defined as encompassing a variety of emotionally, physically,

and sexually neglectful, demeaning, and aggressive behaviors. According to the Declaration on

the Elimination of Violence Against Women, the United Nations General Assembly defines

violence against women as "any act of gender-based violence that results in, or is likely to result

in, physical, sexual, or psycbological hmor suffering to women, including threats of such acts,

coercion or arbitrary depnvation of liberty, whether occurring in public or private life" (United

Nations, 1993).

The manner in which violence has been defined and operationalized within violence research has varîed depending on the theoretical hmework adopted by the investigators (Gelles & Loseke,

1993). The feminist perspective locates violence within a system of unequal power relations between women and men (Yllti, 1993). Therefore, any action that fùnctions to control women is included in the dehition. Examples of emotionally abusive and controlling behaviors include acts of intimidation, insults, control of finances, jealousy of other men, and making light of the abuse. Physical violence includes both threats and actions, and encompasses such behaviors as slapping, pushing, punching, choking, using or throwing objects or other weapons that could result in injury. Child neglect also characterizes a form of abuse and represents the failure of caregivers to provide the required necessities of life (physical neglect) and the withholding of affection (emotional neglect). Sexual violence also includes both threats and acts, and is often classified as either having involved physical contact (e.g., touching of victim's or offender's genitals, breasts, buttocks etc, sexual intercourse, and oral-genital or anal-genital contact) or no- contact (exposure of offender's genitals or requests for sexual involvement) (Painter, 1986).

2.5.1.2 Extent and nature of violence in childhood

General population surveys estimate the lifetime prevalence of childhood victimization in women to be significant. These studies also reveal that most assaults are committed by individuals lcnown to the victim and ofien occur in private homes, places that are usually considered safe for children. The various types of abuse often CO-occur.Threats, intimidation, or physical coercion may accompany sexual assaults.

The classical study in this area was by Russell (1986) who interviewed a random sample of

930 San-Francisco-area women. The data revealed that at least one incident of child sexual abuse

(before the age of 14) involving physical contact was reported by 28% of the respondents. When contact and non-contact sexual experiences were combined, 48% of women reported at lest one such incident. Although the majority of sexual assaults involved touching or fondling, many women reported more severe types of experiences. Approximately one in four (23%) women who reported abuse were classified as having experienced 'very serious' sexual assaults (e.g.,

forced intercourse, attempted intercourse, forcible or non-forcibie fellatio, cunnilingus,

analingus), 4 1% 'senous' abuse (forcible or non-forcible contact with genitals or other unclothed

sexual body parts), and 36% expenenced 'lem senous' sexual abuse (forcible or non-forcible

kissing or sexual touching of other body parts). Almost al1 perpetrators (96%) were men, rnost of

whom were hown by the victim. Only 1 1% of the perpetrators were strangers, whereas 29%

were relatives, and 60% were known to the women but were unrelated to them.

Badgley (1984) conducted the National Population Survey (the "Badgley Report") in which a

randorn sample of 2008 Canadians in 2 10 cornmunities were interviewed about their experiences of sexual violence. When the cases of the abuse were stratified by sex, girls were more likely to be victims than were boys (74.8% vs. 28.2%). They "Badgley Report" also reviewed data derived fiom hospital, police, and child protection surveys. Congruous with Russell's study,

Badgley found that 98.8% of al1 suspected offenders were men.

The Iifetime prevalence of contact child sexual abuse (under age 16) for women was 33.8%.

When al1 types of assaults (i.e., contact and non-contact) were cornbined, 53 5%of women reported at least one type of abuse experience, and 22.3% reported two or more. These proportions are also comparable to those found by Russell (1986). The study also dispelled the myth that sexual assaults against children are more likely to occur in public places. Over half

(55.4%) of the assaults took place in the homes of either the victim or the perpetrator. Finally, the report concluded that three in five sexually abused children were subjected to threats or physical force during the assault, and one in five cases sustained physical injuries.

A more recent study conducted between 1990 and 1991 was the Ontario Health Survey

Mental Health Supplement. In this study, 9953 men and women 15 years of age or greater were interviewed about their experiences of physical and sexual abuse when they ''were growing up"

(MacMillan et al., 1997). The physical abuse items were derived from the Conflict Tactics Scales

and the sexual abuse items were based on the National Population Survey (i.e., the "Badgley

Report"). The data revealed that the lifetime prevalence of child physical abuse was greater in

men than in women (3 1.2% versus 2 1. lx), whereas the prevalence of child sexual abuse was

greater in women than in men (12.8% versus 4.3%). Furthemore, women were more likely than

men to have reported the CO-occurrenceof physical and sexual abuse (6.7% versus 2.4%). No sex

differences emerged with respect to the proportions revealing satere physical abuse (men =

10.7% versus women = 9.2%). However, severe sexual abuse was significantly more prevalent

arnong women than men (1 1.1% versus 3.9%). Women were also more likely than men to have

reported both types of severe abuse (4.2% versus 1.3%). Perpetrators of physical abuse were most likely to be fathers, followed by natural mothers whereas perpetrators of sexual abuse were most likely to be "some other person", followed by other relatives.

2.5.1.3 Extent and nature of violence in adulthood

The following review is based on national data fiom the 1993 Violence Against Women

Survey (VAWS) (Johnson, 1996) and the 1999 General Social Sruvey on Victimization (GSS)

(Statistics Canada, 2000). The VAWS was a nationally representative telephone survey of 12 300

Canadian women that was conducted in 1993 specifically to assess their expenences of al1 fons of violence, including sexual harasment, threats of violence, emotional abuse, sexual and physical assault. The GSS is a traditional cnminal victimization survey of a representative sample of 26 000 Canadian women and men.

The results fiom the VAWS revealed that approximately one in two (5 1%) women had experienced at least one episode of physical or sexual assault since the age of 16, and in the year

preceding the survey 10% of women had been assaulted. Lifetime prevalence of sexual and

physical assault was 39% and 34% respectively. Twenty-nine percent of women who were ever

married or lived in a cornrnon-law relationship reported having been physically assaulted. Thirty-

five percent of ever-manied women reported some form of emotional denigration or controlling

behavior. As with child abuse, most perpetrators were men who were known to the women

(68%) rather than strangers (23%).

These assaults were usually not isolated occurrences, but involved repeated victimizations

that often escalated in severity and fiequency over time. Sixty-three percent of assaulted women

reported more than one episode and 32% reported more than 10. Close to half (44%) of the

women who experienced violence reported that a weapon had been used against them at some

point during the marriage.

Women who expenenced violence were most often subjected to multiple forms of abuse. in

fact, the strongest predictor of physical abuse was the presence of emotional abuse in the

relationship. Three out of four women who reported physical abuse also reported experiencing

various emotionally abusive, controlling, and demeaning behaviors (e.g., he insists on knowing

her whereabouts, jealousy of other men, calls her narnes to make her feel bad, control of

finances, limits contact with farnily and Wends). Only 18% of women expenenced emotional

abuse in the absence of either sexual or physical assault. Furthemore, as the severity of the

physical abuse increased, so too did the use of these controlling tactics. In fact, 95% of women

who experienced serious, life-threatening abuse also reponed concurrent emotional abuse.

Johnson theorizes this finding as evidence that men use violence as a means of asserting power and control over women. The co-occurrence of abuse types was also demonstrated as 92% of women who were sexually assaulted also experienced some form of physical abuse (e-g., being

hit, slappeà, choked, punched, beaten up, or threatened with a weapon).

The health consequences of such abuse are quite severe and traumatic. According to the GSS,

women were more likely to have experienced severe foms of assault than were men. Women

were also three times more likely than men to have sustained physical injuries fiom the attacks

(40% versus 13%), five times more likely to have received medical attention (15% versus 3%),

and five times more likely to have feared for their lives (38% versus 7%).

2.5.1.4 Extent and nature of violence during pregnancy and the postparturn period

Pregnancy and the postpainun pend represent times in which many women continue to be subjected to abuse and some may even expenence their first episode of violence during this time.

Physical assaults not only pose health risks to women themselves, but violence during pregnancy may negatively affect the health of the fetus. A small body of research has examined the prevalence of abuse during pregnancy and whether the nature of such abuse (i.e., fiequency and severity) changes as a fimction of pregnancy status. Relatively few studies have included an examination of abuse during the postparturn period.

Gazmararian et al. (1996) conducted a literature review of studies exarnining the prevalence of antenatal violence and found that estimates ranged between 0.9% and 20.1%. The majority of studies reported prevalence estimates of between 3.9% and 8.3%. The authors indicated that although the disparity in estimates reported by these studies may be attributable, in part, to differences in the populations examined, they suggest that methodological differences may also account for some of these differences. There is also some indication in the literature that the prevalence of abuse may be greater following childbirth than during pregnancy (Stewart, 1994). Further studies are needed in this area.

With respect to the pattern of violence in the time surrounding pregnancy, women who report antenatal violence are highly likely to have a history of violence pnor to their pregnancy (Ballard et al., 1998), and to continue to be subjected to assaults afier delivery (Stewart, 1994). For many women (22.9% to 5 1.7%), violence experienced during pregnancy represents a continuation of an ongoing pattern of abuse (Ballard et al., 1998). The continuation of violence into the postpartum period is also common. in one study, 90% of women who reported abuse dwing their pregnancy also reported abuse in the 3 months afier delivery (Stewart, 1994).

2.5.1.5 Physical health correlates of violence

2.5.1 S. 1 Abuse experienced during cbildhood

Springs and Friedrich (1992) examined the association between child sexual abuse (CSA) and medical problems in adulthood. They found that the presence and severity of CSA was a significant predictor of lifetime prevalence of medical problems. Women with a history of CSA reported a greater mean number of current or past medical problems than did non-sexually abused women (8.0 versus 6.5). More severe abuse was also associated with an increased frequency of symptom reporting. Sexually abused women who experienced penetration reported an average of 8.6 problems; those who reported multiple abusers had an average of 9.0 problems.

The mean number of gynecological problems also increased with more severe levels of abuse (no abuse = 2.8, CSA = 3.4, CSA and penetration = 4.0).

Walker et al. (1 999a) conducted a general population survey of women who were randomly selected hma large health maintenance organization. They examined the relationship between child maltreatment and adverse physical health outcomes as adults. The cornparison groups included women with subthreshold levels of maltreatment (controls), women with non-sexual

maltreatment, and women who reported sexual maltreatment (alone or in addition to other forms

of abuse). The data revealed a positive association between the extent of abuse and physical

symptoms. Women who reported subthreshold levels of abuse had an average of 1.9 somatic

symptoms, those who reported non-sexual rnaltreatment had 2.7 symptoms, and those who

reported sexual maltreatment had 3.4 symptoms. Women who experienced child maltreatment

also had more medical diagnoses coded than did controls. The authors poshilated that the

increased syrnptom burden in women with sexual abuse was likely due to exposure to multiple

foms of child abuse and neglect that also included sexual abuse, rather than specifically to

sexual abuse pet- se.

The types of medical problems that have been found to be associated with CSA are: learning

disabilities, gynecological problems, pelvic pain, pelvic infiammatory disease, breast disease,

bladder infections, complications of pregnancy, having ever been ovenueight, and having had

more than one operation (Springs & Friedrich, 1992). Walker et al. (1999a) found women with a history of childhood maltreatment had an increased risk of experiencing minor infectious diseases (vaginitis, urinary tract infection, upper respiratory infection, sinusitis, rhinitis, phaiyngitis, bronchitis, cellulitis), hypertension, diabetes, dermatitis, asthma, allergies, and abnormal menstmal bleeding. The somatic symptoms found to be related to child maltreatment include nausea, diuiness, numbness, shortness of breath, fatigue, insomnia, dyspareunia, various pain symptoms including headache, chest, abdominal, back, and joint pain, and sexual problems including sexual anhedonia and anorgasmia (Walker et al., 1999a).

2.5.1 S.2 Abuse experienced during adulthood

Coker et al. (2000) examined the health impact of intimate partner violence expenenced during adulthood. Three cornparison groups were: women who experienced psychological battering in the absence of physical or sexual violence, women who reported physical or sexual violence with or without psychological abuse, and a control group of non-abused women.

Participants were recruited from a primary care setting. The authoa attempted to control for the presence of child abuse using a proxy variable of having witnessed abuse of mother by father.

Psychological battering in adulthood was found to be associated with various pain symptoms

(chronic neck or back pain, chronic pelvic pain, migraines and other fkequent headaches), arthritis, digestive tract problems (stomach ulcer, gastric reflux, indigestion), and GI problems

(constipation, diarrhea). Physical or sexual violence was also associated with most of these symptoms, in addition to various other medical problems including vision and hearing problems, angina, heart and other circulatory problems, bladder and kidney infections.

2.5.1.5.3 Abuse experienced during childhood and/or during adulthood

McCauley and colleagues (1997) ascertained the health consequences of physical and sexual violence experienced in childhood and in adulthood. This study was unique in that it isolated the specific effects of abuse experienced in childhood and in adulthood, as well as the cumulative impact of being exposed to both forms of trauma. With respect to child abuse, few differences were observed between sexual and physical violence. The only difference that emerged was that patients who experienced both forms of abuse reported slightly more physical symptoms than did those who reported physical abuse only. Generally, patients who reported any form of child abuse (but not adult abuse) reported experiencing more physical symptoms in the previous 6 months than did non-abused controls (6.2 versus 4.0). In fact, women who reported six or more symptoms were four times as likely to report being abused as children than those who reported between zero and two symptoms.

2.5.1 -5.4 Functional disability and health care utilization

Women who expenence a history of violence also report more irnpaired functional ability than do women without such a history. The HM0 study conducted by Walker and colleagues

(1999a) found that women who reported any form of childhood abuse or neglect were more likely to rate their health as fair or poor and to have lower physical role fûnctioning ability than women who reported subthreshold levels of child abuse. Coker et al. (2000) found that compared to non-abused controls, women who expenenced psychological battering and physical or sexual violence as adults were more likely to rate their physical health as being poor. Women who reported physical or sexual violence were also more likely than control subjects to experience a disability that interfered with work.

The health impact of violence is also demonstrated by the finding that women with a history of violence use health care system to a greater degree than women who do not report such a history. Walker et al. (1 999b) used health care use and cost data fiom a large HM0 to examine the association of these variables to maltreatment in childhood. They found that women who reported a history of any child maltreatment had median total health care costs that were $97 greater than that for women with betow threshold levels of child maltreatment. The median costs incwed for women who experienced sexual maltreatment was $245 greater than that for controls. Compared to controls, women who reported any form of abuse were more likely to have accessed mental health services, and women who reported sexual abuse were more likely to have had a visit to the emergency department. The greater cos& and use for wornen in the sexual maltreatment group was likely due to having been exposed to multiple forms of abuse, including sexual violence.

Finally, the study also provides evidence for the cumulative health impact of violence. A

positive association was found between the number of child maltreaûnent categones and health

care costs incurred.

2.5.1.6 Models explaining the relationship between violence and physical symptoms

Numerous models have been proposed to explain the mechanism by which interpersonal violence affects women's physical health. Resnick et al. (1997) provide a synthesis of the available violence literature and describe a mode1 based on their review. They first differentiate physical health problems into acute physical injuries and long-term chronic health problems.

First, women subjected to physical or sexual violence may incur physical injuries directly resulting from the attack. Such injuries include bruises, contusions, fractures, dislocated joints, and tom muscles or tissues. Women may also expenence longer-term vision or hearing problems or a loss of dexterity as a consequence of chronic and repeated trauma. Victims of rape may suffer genital injuries and lacerations fiom the attack, and have an increased risk of contracting a sexually transmitted disease including the human immunodeficiency virus (HlV). Longer-term physical health problems associated with a sexually transmitted disease may include pelvic inflammatory disease.

Resnick et al. (1997) describe a second mode1 where health risk behaviors mediate the relationship between violence and physical health. Individuals subjected to violence are more likely to smoke, consume an excessive amount of alcohol, and take drugs, perhaps as a means of coping with the violence itself or the effects of the abuse. hdividuals with a history of violence are also more likely than those without such a history to have a poor diet, and to avoid preventative health appointments such as gynecological exarninations. Many of these health risk behaviors are known risk factors for various diseases and other physical health problems.

Resnick and colleagues (1 997) also discuss evidence suggesting that physical health problems may be mediated by the psychological sequelae of violence, particularly depression, anxiety, and pst-traumatic stress disorder. Somatic symptoms and other physical health problems have been shown to be associated with these negative psychological health experiences.

Finally, stress resulting fiom interpersonal violence may induce changes in endocrine system fiinctioning, may cause chronic physiological arousal of the central nervous system, or may suppress immune system fùnction, al1 of which may lead to an increased risk of physical health problems. 2.6 Depression and health

2.6.1 History of depression (study objective #2)

Numerous studies have established a link between depression and physical health symptoms.

hdividuals with a clinical diagnosis of depression or who experience depressive-like symptoms

are more likely to report various somatic complaints, chronic medical problems, more fùnctional

disability, and more fiequent use of the health care system than those without depression. Katon

(1984) conducted a review of the literature on depression-related physical symptoms and found

that depressed patients are more likely to present to primary care setting than to mental health

settings, and are more likely to present with vague physical complaints than with overt

psychological problems.

2.6.1.1 Definition of depression

Depression is described as encompassing psychological, cognitive, and physical dimensions.

The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) (Arnencan Psychiaûic

Association, 1994) includes nine symptoms for major depressive disorder (MDD):depressed mood, loss of interest or pleasure in activities, feelings of woithlessness or guilt, impaired ability to think or concentrate, significant weight loss or weight gain, insomnia or hypersornnia, psychomotor agitation or retardation, fatigue or loss of energy, and suicida1 ideation. The diagnostic criteria for MDD specify that five or more of these symptoms must persist for at least

2 weeks, and must include either depressed mood or loss of interest or pleasure.

2.6.1.2 Physical health correlates of depression

The question arises as to whether somatic symptoms are a unique feahire of depression per se, or whether they are a more diffise characteristic of psychiatric illness more generally. Using data obtained fiom the U.S. population-based Epidemiologic Catchent Area ~tudy'(ECA), Simon and VonKorfY (1 99 t ) investigated whether somatization (Le., the reporting of medically unexplained physical symptoms) was associated with specific psychiaûic disorders.

Somatization was assessed using the 37-item somatization subscale of the Diagnostic Interview

Schedule (DIS). Of the psychiatric diagnoses examined, major depression was the strongest correlate of somatization, followed by anxiety disorder. Smaller correlations were found for schizophrenia, mania, antisocial personality, and alcohol abuse or dependence.

The ECA study also found a dose-response relationship between the number of somatic syrnptoms reported and the concurrent risk of depression. That is, as the number of current somatic syrnptoms increased, so too did the proportion of respondents with either major depressive disorder (MDD) or depression-related symptoms (i.e., depressed for 2 weeks, depressed for 2 years, feel worthless or guilty, crying spells, feeling hopeless). In fact, respondents who reported five or more somatic symptoms had a relative odds of major depression that was 16.9 times greater than that for respondents who reported no sornatic symptoms.

The association between somatic symptoms and depression has also been supported in other studies. An international study of primary care patients, conducted in 14 countries on 5 continents also demonstrated that those with major depression reported significantly more unexplained somatic symptoms than did non-depressed patients (4.2 versus 1.2; -OR = 3.5; 95%

-CI = 3.3 - 3.8) (Simon et al., 1999). Katon (1 984) conducted a prospective study of patients presenting to a variety of medical specializations and found that somatizers were 2.5 times more likely to have major depression than were non-somatizers. Depression was found in 48% of patients with unexplained physical symptoms. Major depression was also found to be the most

cornmon psychiatric diagnosis among somatizers.

Studies using simples of patients presenting to pnmary care facilities also demonstrate that

depressed patients often report concurrent physical health symptoms. Duer et al. (1988) found

that depressed individuals reported more somatic symptoms (e.g., chest pain, back trouble, body

pain) and more chronic medical problems than did non-depressed medical controls. Katon and

Russo (1989) found that depressed patients had a greater mean number of somatic symptoms

than did a medical control group that did not have any lifetime psychiatric diagnoses.

Using a comrnunity-based sample selected fiom a health maintenance organization, Breslau

and Davis (1993) demonstrated a significant association between a lifetime history of major

depression and a lifetime history of migraine headaches.

The types of physical symptoms that have been found to be associated with depression

include malignancy and nonspecific or ill-defined symptoms (Coulehan et al., 1990), decreased

energy levels, poorer self-rated health, specific chronic conditions including arthritis and

hypertension, chronic pain (stifniess, swelling, and aching, headaches, chest pain), and fatigue

(Duer et al., 1988).

One study that examined the association between MDD and a lifetime history of 18 different

health problems revealed the strongest association between MDD and fiequent or severe

headaches and migraine headaches (Moldin et al., 1993). This association was strongest for

women. Other illnesses found to be associated with MDD included skin infections, respiratory

illness, stomach ulcer, hypotension, and diabetes (Moldin et al., 1993).

Magni et al. (1990) conducted a population-based US study and found a significant association between depressive symptoms, as measured by the Centre for Epidemiologic Studies Depression scale (CES-D),and chronic musculoskeletal pain (Le., neck pain, back pain, hip, knee pain, swelling and pain of the joints on most &ys for at least 1 month occurring during the year pnor to the interview).

2.6.1 .S. 1 Functional disability and health care utilization

Depressed patients may also expenence marked impairment in their fùnctional ability in the domains of physical, role, and social wellbeing (Wells et al., 1989). An investigation using data fiom the Medical Outcornes ~hidf(MOS) (Wells et al., 1989) demonstrated that the functional ability of depressed patients was significantly worse than that for patients with various chronic medical conditions. With respect to physical functioning specifically (i.e., limitations in daily and self-care activities including dressing, bathing, walking, climbing stairs, sports), depressed patients fared worse than patients with gastrointestinal problems, arthritis, a history of diabetes, and hypertension. Their physical fhctional ability was superior only to patients with heart disease (angina and coronary artery disease). Depressed patients also rated their health as significantly worse than did patients with al1 other medical conditions, with the exception of those with heart disease. Finally, depressed patients reported greater bodily pain than did patients with the five other conditions, including those who had angina.

Depressed individuals also use the health care system to a greater degree than non-depressed individuals (Simon, 1992). In this study, female respondents with major depression reported a greater mean number of general medical visits in the previous 6 months than did control subjects with no psychiatric diagnoses (5.7 versus 2.2). Mental health visits were also more fiequently reported by depressed patients compared to those fiee of any psychiatric diagnoses (women: 2.5 versus 0.3; men: 2.7 versus 0.3). 2.6.1.3 Models explaining the relationship between depression and physical symptoms

Katon (1984) presents of a review of the literanire on depression and physical symptoms and describes some of the mechanisrns that have been postulated to mediate their relationship. In the fint model, depression is precipitated by severe or chronic medical illness. According to this model, illness results in changes in the central newous system, which are also related to the occurrence of depression. Although this is one possible explanation, Katon states that the more likely scenario is that depression is a consequence of ernotional distress among individuals who are chronically or acutely ill. One study reviewed in the paper demonstrated that depression was the most cornmon psychiatrie disorder among those with medical disease.

The second model proposes the reverse relationship, that depression precipitates the onset of physical health problems. The third rnodel suggests that depression fimctions to ampli@ sensory experiences of somatic symptoms and physical illness. That is, depressed individuals may be more sensitive to somatic expenences and may more likely to perceive physical problems as being more severe than non-depressed individuals. This model explains why underlying organic problems may not correlate with actual symptom severity ratings reported by depressed patients.

The final model, derived fiom a psychoanalytic fiamework, describes somatization as a deflected expression of psychological distress in individuals who are unable to acknowledge or express these psychological symptoms. This charactenzation describes the personality trait known as alexithyrnia.

The World Health Organization's international study tested the occumnce of three different definitions of somatization of depression (Simon et al., 1999). Among patients with MDD, the psychoanalytic explanation was relatively uncornmon. Only 1 1% of depressed patients presented to primary care with somatic symptoms and denied the presence of psychological distress when

directly questioned about it. The second model (somatic presentation) was most prevalent. The

majority of depressed patients (69%) reported physical symptoms as the reason for their visit, but

readily acknowledged psychological symptoms when asked. Interestingly, this form of somatized

depression was more common in walk-in centres than in clinics where patients had established an

ongoing relationship with a specific caregiver. The authors speculated that a somatic presentation

might be more acceptable or expected in a pnmary care setting, to both patients and caregivers.

The third model evaluated the CO-occurrenceof somatic and psychological symptoms of

depression. As previously noted, the study found that those with MDD reported significantly

more somatic symptoms than did those without MDD. Furttiermore, 50% of depressed patients

also met the clinical criteria for multisomatofonn disorder (i.e., at least three unexplained

somatic symptoms). Based on these results, the authors concluded that "somatic symptoms are a core component of the depressive syndrome" (p. 1333).

Furiher support for the link between psychological and physical symptoms in depression is provided in a study that examined the temporal pattern of changes in symptoms that were associated with antidepressant dmg treatment (Casper et al., 1994). The data revealed that improvements in loss of appetite, weight, and sexual interest closely mirrored the timing and pattern of mood changes. Although sleep patterns did not follow the same pattern, they did tend to normalize after depressed mood was alleviated. 2.7 Other factors

2.7.1 Other psychosocial factors

Social support is broadly defined as including both stmctmtl and functional measures.

Structural measures represent a more objective conceptualization of support as the presence or

absence of social ties or networks (Ganster & Victor, 1988). Functional social support represents

a more subjective rating of the quality of social relationships and companionship. In the present

study, we assessed women's perceptions officnctional social support received fiom farnily

members and fiiends during the postparturn penod.

A literature review by Bruhn (1996) presents evidence in support of a negative association

between social support and physical symptoms and mortality. Low social support has been found

to be associated with an increased risk of al1 cause mortality, cardiovascular disease including

heart attacks and mortality due to heart attacks. There is some indication that social networks

may affect health by promoting recovery fiom such diseases as cancer, stroke, or hem disease,

rather than by directly preventing the occurrence of the disease. A literature review by Rosenfeld

(1 997) also describes evidence in support of an association between low social support and various health outcomes including mortality, heart disease, and negative pregnancy outcomes such as matemal complications.

We also examined the association between a history of traumatic life events and postpartum physical well-being. According to the fourth edition of the Diagnostic and Statistical Manual of

Mental Disorders @SM-IV), a traumatic event is defined as an experience that causes or could potentially cause injury or death, or that threatens one's physical integrity (American Psychiatric

Association, 1994). Examples of such events include king involved in a war, a natural disaster, a life threatening accident, or a king threatened or assaulted. The event may be experienced personally and directly, or indirectly, such as having witnessed a plane crash or having heard that someone close had experienced such an event.

Ullman and Siegel (1996) studied the association between a history of traumatic life events and physical health status in a community sample. They found that respondents who had indicated at lest one distressing traumatic experience in theu lifetime reported more limitations in their physical functioning, more chronic medical problems, and poorer self-rated physical health than respondents without a history of trauma.

2.7.2 Sociodemographic factors

Social class differences in health status have been well established in the literature. An inverse relationship between health and factors such as income, education, and occupational class has been observed (Mackenbach et al., 1997). The relationship between social class and health has been described as a gradient, each increment class statu being associated with a decrease in morbidity (Marmot et al., 199 1). Some research has also documented racial or ethnic differences in health, however these differences may partly be a due to the confounding of social class differences (for a review see Benzeval et al., 1995; Smith, 2000).

2.7.3 Health care-related factors, including materna1 and obstetrical factors

2.7.3.1 Epidural analgesia

Thorp and Breedlove (1 996) conducted a literature review of the risks and benefits associated with epidural use during childbirth. They found that the most comrnon maternal heakh problems arising hmepidural analgesia were hypotension, inadvertent dural puncture, matemal fever, and spinal headache. According to the studies reviewed, these symptoms are usually self-limiting, easily ~atable,and rarely evolve into chronic health problems. The procedure was also found to be associated with longer length of labour and operative intervention (Le., c-section and assisted delivery). Although epidural use bas been postulated to increase the risk of chronic back pain, the authors concluded that the existing evidence for this association was inconclusive.

2.7.3.2 Length of stay

Braveman et al. (1995) conducted a literature review of research evaluating the safety of early hospital discharge for healthy mothers and newbom infants. In their analysis, they use the defmition of early discharge delineated by the Arnencan Academy of Pediatrics. For uncomplicated vaginal deliveries, "early" and "very early" discharges are stays of 48 and 24 hours or less respectively. For caesarian section births, early discharge is a stay of 48 to 72 hours.

Based on their review, they concluded that the majority of studies in this area lacked statistical power, had numerous other methodological flaws, and that effects of early discharge on matemal hea1th have been inadequately studied.

2.7.3.3 Episiotomy

Woolley (1 995a, 199513) performed an extensive literature review of research investigating the consequences of episiotomy on matemal and fetai health. With respect to materna1 health, the review evaluated the medical assumptions claiming that episiotomy reduces the risk of perineal lacerations, that it is preferable to spontaneous tearing because it is easier to repair, and that it prevents against pelvic floor relaxation. Woolley (1995a) found that the only benefit derived

6rom episiotomy was that it prevented against antenor perineal damage, which typically results in minimal negative sequelae. The evidence did not support the remaining claims. in fact, many studies demonstrated increased materna1 morbidity associated with the procedure. Women who had an episiotomy were more likely to suffer third- and fourth-degree perineal lacerations. The procedure was also associated with longer time be fore resurning sexual intercourse, increased

materna1 blood loss at delivery, risk of improper wound healing in the early postpartum period,

and early postpartum perineal pain (during the first few postpartum days).

2.7.3.4 Mode of Birth

Brown and Lurnley (1998) surveyed women six to seven months after childbirth and

ascertained the prevalence of nwnerous postpartum matemal health problems, and the

association between these symptoms and obstetrical factors. With respect to mode of birth,

comparisons were made between four groups of women: those with an unassisted vaginal birth,

assisted vaginal birth (forceps or vacuum extraction), emergency c-section, and elective c-

section. The data revealed that women who had had an assisted delivery experienced the highest nsk of self-reported health problems. Assisted delivery was associated with perineal pain, sexual problerns, bowel problems, urinary incontinence, and hemorrhoids. Compared to those who had had an unassisted delivery, women who had delivered by caesarian section reported similar or lower number of postpartum symptoms. The problems that were less prevalent among women who had caesarian births were urinary incontinence, and hemorrhoids.

Glazener et al. (1995) evaluated matemal health outcomes associated with mode of delivery.

The findings largely substantiated those of Brown and Lumley (1 998), implicating assisted vaginal deliveries as a risk factor for matemal health problems. Women with an assisted delivery were more likely than women with an unassisted vaginal delivery or a caesarian delivery to have reported at least one health problem between O and 13 days postpartum, at 8 weeks postpartum, and between 2 to 18 months postpartum. Cornmon health problerns were perineal pain, constipation, piles, and stitches breaking down.

2.7.3.5 Panty Glazener et al. (1995) a1so evaluated postpartum matemal symptoms associated with parity.

They found that within the first two postpartum weeks, primiparous women (i.e., those for whom the index birth was their first) reported significantly more health problems than did multiparous women (i.e., women who had had at least one previous birth). Most of these problems were self- limiting. The problems that were more fiequently reporied by primiparous were anaemia, vaginal discharge, painfui perineum, and piles.

2.8 Literature review of instruments used in the study

2.8.1 Postpartum Depression (Edinburgh Postnatal Depression Scale)

The Edinburgh Postnatal Depression Scale (EPDS)(Cox et al., 1987) is a 10-item scale that assesses the affective symptoms of depression such as depressed mood, anhedonia, anxiety, guilt, and suicida1 ideation. It excludes the somatic featwes of depression such as fatigue, insomnia and changes in appetite, which ofien reflect the normal physiological changes in postpartum women.

Although the EPDS was originally developed to be used as a screening tool for postpartum depression (PPD) in a community setting, it has subsequently been used in other populations, including in fathers (e.g., Areias et al., 1996; Ballard et al., 1994) and in pregnant women (e.g.,

Cooper et al., 1996; Dennerstein et al., 1989), and in various other research settings (e.g.,

Campbell & Cuhn, 1991;Schaper et al., 1994; Wamer et al., 1996).

The original validation study (Cox et al., 1987) established the concurrent validity of the instrument by comparing EPDS scores to clinical diagnoses of depression made using the

Research Diagnostic Criteria (RDC) obtained fiom Goldberg's Standardized Psychiatric

Interview. The instrument was also found to be sensitive to changes in the severity of depression over time. Other researchers have also tested the psychomeûic properties of the scale (e.g., Harris et al., 1989; Murray & Carothers, 1990; Wickberg & Hwang, 1997; Zelkowitz & Milet, 1995).

Murray and Carothers (1990), for instance, tested the scale against the RDC and detennined the sensitivity, specificity, and positive predictive value associated with different EPDS thresholds.

They found that a threshold of 11.5 yielded test sensitivities of 88% and 63.5% for major and minor depression respectively, test specificity of 92.5, and a positive predictive value for major depression of 35.1 %. A threshold of 8.5 yielded test sensitivities of 97.8% and 88.4% for major and minor depression, test specificity of 74.6%, and a positive predictive value for major depression of 18.0%. Wickberg and Hwang (1997) compared the EPDS against the DSM-III-R diagnosis for major depression and fond that a threshold of 1 1.5 yielded a test sensitivity of

96%, a test specificity of 49%, and a positive predictive value of 59%.

2.8.2 Violence instruments

2.8.2.1 The Psychological Maltreatment of Women inventory

The Psychological Maltreatment of Women hventory (PMWI) (Tolman, 1989), is a 58-item instrument that was developed to assess the nonphysical forms of abuse perpetrated by a woman's partner. Because the complete instrument would have been too long for the interview only eight of the questions were used and four new questions were added. Respondents were asked to rate the fiequency with which each of the events occurred during the previous 12 months using a 5-point scale (O to 4) ranging fiam -never to very often. The minimum and maximum possible scale scores were O and 48 respectively.

Factor analyses conducted in the original study (Tolman, 1989) revealed that the instrument assesses two dimensions of psychological abuse. The first scale represents a dominance-isolation factor and assesses such features of abuse as the restriction of contact with family and fiiends, jealousy, and monitoring women's time and whereabouts. The second scale represents an

emotional-verbal abuse factor and includes behaviors and verbal insults intended to attack

women's sense of self worth. Both subscales demonstmted high intemal consistency; the alpha

coefficient for the dominance-isolation factor was 0.95 and that for the emotional-verbal factor

was 0.93.

2 X2.2 The Revised Conflict Tactics Scales (CTSS)

The Conflict Tactics Scales (CTS) (Straus, 1979; Straus et al., 1996) is one of the most widely

used instruments within violence research. The onginal instrument consists of 19 items assessing

the use of reasoning, verbal aggression, and physical aggression within the context of an intimate

relationship. The revised Conflict Tactics Scales (CTS2) (Straus et al., 1996) was developed to

enhance and expand upon the original CTS. It is a 39-item questionnaire that measures specific

negotiation tactics, acts of psychological aggression, and physical assault. It also assesses two

constructs that were lacking fkom the original instrument; namely, sexual coercion and physical

injury resulting fiom the violence.

2.8.2.3 The Violence Against Women Survey

The five emotionally abusive and controlling spousal violence items fiom Statistics Canada's

Violence Against Women Survey (VAWS, 1993) (as listed in Johnson, 1996, p. 16 l), were used

in the present study. The VAWS was a nationally representative telephone survey of 12,300

Canadian women 18 years of age or older that assessed their experiences violence since the age of 16. The survey included questions assessing a broad range of experiences including sexual harassment, women's fear of public places, emotional, sexual and physical assault. in the present study, the timeheof the items were changed such that participants were asked to indicate whether or not they had experienced each event in the two years before the pregnancy, during the pregnancy, and after the birth. Women who answered yes to any of the items then rated the

fkequency with which each event had occurred on a 4-point rating scale ranging froin rarely to

very often.

2.8.2.4 The Abuse Assessment Screen

The Abuse Assessment Screen (AAS) (McFarlane et al., 1992) consists of five questions that

assess physical violence experienced in the remote past, during the previous 12 months, and

during pregnancy; sexual abuse during the previous 12 rnonths; and fear of her partner or anyone

else (McFarlane et al., 1992). A three item version of the AAS was validated against the Conflict

Tactics Scales (Straus, 1979) and the index of Spouse Abuse (Hudson & Mchtosh, 198 l), and

was found to be sensitive and specific to the abuse status of respondents (McFarlane et al., 1992).

2.8.3 Traumatic life events (The National Comorbidity Survey)

Most of the traumatic events that were assessed were obtained fiom the Arnerican National

Comorbidity Survey (NCS) (Bromet et al., 1998). The survey involved a face-to-face interview of 5877 respondents and examined the association between 11 types of traumatic expenences and posttraumatic stress disorder (PTSD). The instrument also included one open-ended question that allowed respondents to repon any other traumatic experiences. In the present study, participants who reported having experienced any of these traumas were Merquestioned about the timing of the event and the psychological impact that it currently bad on them. Those who indicated multiple traumas were asked to select the one that had been most troublesome for them. 2.9 S-W

There is a dearth of studies that have documented the physical health symptoms and problems that women commonly encounter following childbirth. Furthemore, studies that have examined possible risk factors for negative postparturn health outcornes have focussed primarily on medical and health-care related factors, many of which are specific to the prepancy experience.

Little is known about the manner in which psychosocial factors affect women's postparturn physical well-being. Research on the health determinants that are central to the lives of many women, such as violence and depression is sorely lacking within this population. Generating a more comprehensive understanding of women's postpartum physical health couid aid clinicians in providing pregnancy-related care to women. informing new mothers about postparturn health adjustment would better enable women to take control of their health and to make personal decisions surrounding it. METHODS

3.1 Smdy design

A selective prevalence study design was used. Eligible women were identified in the hospital

the day after delivery and were approached to participate in the study at that time. The research

nurse explained the study to potential participants and administered a brief socioeconomic swey

to those who consented to participate. Women's medical records were used to obtain information

about the characteristics of their pregnancy, labour and delivery. Finally, participants were

interviewed by telephone 8 to 10 weeks postpartum.

3.2 Study setting

Participants were recruited fiom one of six hospitals located in the Greater Toronto Area

(GTA). The participating hospitals consisted of three teaching hospitals and three large community hospitals. The teaching hospitals were St. Michael's Hospital, Mount Sinai Hospital, and the Women's Coliege Hospital site of Sunnybrook and Women's College Health Sciences

Centre. The comrnunity hospitals were North York General Hospital, St. Joseph's Health Centre, and the Centenary Health Centre site of the Rouge Valley Health System. These six hospitals were selected for the study, in part, because they had a large number of deliveries that would expedite subject recruitment. The number of deliveries reported by these hospitals between 1996 and 1997 was: Centenary Health Centre, 2520; Women's College Hospital, 3856; Mount Sinai

Hospital, 4244; St. Joseph's Health Centre, 239 1; North York General Hospital, 3828; St.

Michael's Hospital, 1956. These hospitals also serviced a wide range of socioeconomic and ethnic groups. Recruitment was conducted consecutively within the participating hospitals. 44 The study was based in the Violence and HeaIth Research Initiative at the Centre for Research

in Women's Health, a research facility affiliated with the University of Toronto and Sunnybrook

and Women's College Health Sciences Centre.

3.3 Participants

Postpartum women were eligible if they had delivered at any of the six participating hospitals

during the recruitment phase of the study. Participant recruitment took place between January 4,

1999 and September 23, 1999. The following inclusion critena were used to determine women's

eligibility for the study:

at least 18 years of age able to understand and speak English gave birth to a full-term, healthy, singleton infant not giving the baby up for adoption informed consent given capable of being contacted by telephone for the postpartum interview

Due to resource limitations, it was not economically feasible to have the study materials translated into languages other than English and to hire many interviewers who were fluent in these languages. Consequently, women who were unable to understand and speak sufficient

English were excluded fiom the study. An attempt was made, however, to make the study as accessible to as many women as possible by simpli@ng the language that was used in the forms and the interview. Thus, many women for whom English was not their first language were still able to participate in the study and to cany out the postpartum telephone interview.

Women who were under the age of 18 were also not eligible to participate in the study.

Because one of the nsk factors under investigation for this study was having had a history of violence, the decision to implement this age exclusion was based on a consideration of the legal implications of cases in which young participants disclosed abuse during the interview. The law specified in Ontario's Child and Family Services Act (CFSA) section72 (l), indicates that members of the public, including professionals who work with chiidren (i.e., those under the age of 16), have a duty to report to the Children's Aid Society cases in which they know or suspect that a child is in need of protection (Ministry of Comrnunity and Social Services, 2000).

Consequently, if during the study a young participant revealed ongoing or current abuse, then it would have been necessary to report that abuse to the authorities. We did not consider it appropriate for this to occur in the context of a research setting. A cutoff of 18 years was thus used to ensure tbat only adults would be eligible for the study.

Finally, women who were planning on giving their child up for adoption were not eligible for the study. Also, women who had had a multiple or premature birth, a stillbirth, an infant with a congenital illness or requiring the use of the neonatal intensive care unit were also excluded f5om the study. These exclusions were implemented as we did not wish to impose added burden or stress upon these women during this dificult time. We do recognize that excluding these women fiom the study rnay lirnit the external validity (i.e., generalizability) of the study fmdings.

Specificalty, it is plausible that these women may have ken at increased risk for expenencing more postpartum health problems compared to those who met the eligibility cnteria for the study.

Excluding these women fiom the study may have therefore resulted in a less than representative sample with respect to the potential range and severity of postpartum heaIth problems experienced by women in the general population. These women may, for instance, have had a history of persona1 health problems including problems dwing their current pregnancy, a more difficult labour and delivery, or a heightened level of psychological stress during and after their pregnancy. Any of these factors may have placed them at increased risk for experiencing more postpamim health problems. In addition to underestimating the outcome variable, these exclusions may also have resulted in underestimating the prevalence or severity of some of the predictor variables (e-g., depression during pregnancy, matemal complications) if these women were also at increased risk of experiencing these probiems. Since few data were collected on those who were excluded fkom the study, it was not possible to ascertain whether they actually differed f?om study participants on these important dimensions. The results of the study will therefore be interpreted with these limitations in mind.

3.3.1 Sarnpling

A stratified sampling procedure was used whereby each hospital constituted a stratum. The objective was to recruit a total of 240 participants for the study, 40 fiom each hospital. The use of a stratified design helped to ensure that a sample of obstetrical patients was obtained for each hospi ta1 .

3.4 Procedure

Ethics approval was first sought fiom each of the participating hospitals. Two female research nurses, who were specifically hired to work on this study, performed al1 of the subject recruitment. AAer arriving at the hospital, the ward personnel provided the research nurse with the names of women who had recently delivered. The research nurse then identified those women who were eligible for the study and those who were not based on the inclusion and exclusion criteria. The nurse then approached each eligible woman individually and invited her to take part in the study. Although the research nurses attempted to approach al1 eligible women, they were not always able to do so. Factors such as women having had a short length of stay or many visitors prevented this hmhappening. Section 4.1 of the Results Chapter provides a description

of the response rates for the study.

Potential participants were invited to take part in a study that investigated the factors affecting

women's health following childbirth. It was explained that since most existing studies on

pregnancy focused on infant health, the present study was important because it would provide

researchers with a better understanding of the unique factors and stressors that were relevant to

matemal health afier delivery. Potential participants were told that the interview would involve

questions about their health during and after their pregnancy, their level of social support, marital

status, education and employment status, conflict and stresses in their lives, and major life events

that they may have experienced. Aithough they were not specifically told the main hypotheses of

the study, they were informed that the interview might contain some questions that were of a

sensitive nature.

Women were asked to participate in a telephone interview that would take place in 8 to 10 week's time lasting between 30 to 40 minutes. Women who consented to participate then signed a consent form and were asked some sociodemographic questions. They were also given an information sheet describing the study to take home with them. Finally, women were asked if the research nurse could review their medical records to obtain information about their pregnancy, labour, and delivery. The nurse then performed the chart review using a stmctured fom that was specifically designed for this study.

During the recruitment phase of the study, the research nurses kept daily records of the following information: 1) the total number of women on the postpartum ward, 2) the number who were eligible for the study, 3) the number who were ineligible, and 4) the reasons for their exclusion, 5) the number who were approached to participate, 6) the number who were recruited, 7) the number who refused participation, and 8) the reasons for their refûsal. These data were used in the calculation of the recmitment response rates for the study.

Participants were subsequently contacted by telephone 7 to 8 weeks later in order to set up a convenient time for the postpartum telephone interview to take place in private. Up to eight calls were attempted at various times of the day and on different days of the week before an individual was considered a non-respondent. The interviews were scheduled to take place between 8 to 10 weeks postpartum. Al1 interviews were conducted by four female interviewers.

3.5 Instnunents

3.5.1 Labour and birth unit questionnaire

This brief survey was used to obtain sociodemographic infomation about the participants and was based on Statistics Canada's National Population Health Survey (Tambay & Catlin, 1995). It included questions about participants' country of birth, the language firçt learned in childhood, marital status, employment stahis, highest level of educationai attainrnent, and size of cument household. Questions about the partner's employment status and educational attainment were also included. Finally, women were asked to indicate their combined household income by selecting the most appropriate category fiom a predetermined list of options. These response categories were derived fiom Statistics Canada Low-Income Cut-Offs (LICO),for an average sized family of four living in Toronto (Canadian Council of Social Development, 1996). The

Low-hcome Cut-Offs are calculated to reflect the cost of living for families of various sizes that are 1iving in di fferent sized cornmunities.

Chart review form The research nurse abstracted information fiom participant's medical records regarding the

pregnancy history, any existing medical conditions, medical problems during the pregnancy, and

medications used at the time of admission to the hospital. Information was also collected about

the characteristics of the labour, including the onset of labour, type of analgesia or anaesthesia

used, presence of an episiotomy, degree of perineal trauma, length of labour, presentation of

infant at birth, mode of delivery, and maternal complications. Finally, the sex, birth weight and

gestational age of the baby were noted.

3.5.3 Postpartum telephone interview

3.5.3.1 Pregnancy and breastfeeding

The fkst section of the postpartum interview was intended to collect additional information

about the pregnancy. Participants were asked when they first sought prenatal care, whether they

had to take sick leave or were hospitalized during their pregnancy, their perceived level of pain during the labour and birth, and any maternal complications arising fiom the delivery. Women were also asked about breast-feeding and whether they had received any assistance with housework since the birth of the baby.

3.5.3.2 . Postpartum somatic symptoms (Brown & Lumiey, 1998)

This self-report list of somatic symptoms comprised the main outcome measure of this study.

It assessed 13 physical symptoms comrnonly experienced by women after childbirth and was based on a survey conducted by Brown and Lumley (1998). The research assistant read each of the symptoms, and participants were asked to indicate whether any had been problematic for them at any time following the birth. Women were also asked to report any other health-related problems that they had experienced that were not on the list. We did not attempt to ven@ the presence of these symptoms using clinical assessments or

participants' medical records, but rather, relied on participants' self-reports. In fact, most of the

health problems that were assessed (e.g., perineal pain, headaches, backaches, and excessive

fatigue) are not eady diagnosable using objective modes of assessment because they are

detennined by women's own subjective experiences and evaiuations of their own health.

3.5.3.3 Reproductive health

During this section of the interview, women were questioned about menarche, premenstmal

syndrome, and the regularity of their menstrual periods. Women were also asked about the

intendedness of their pregnancy; that is, whether it was planned, wanted or both. A final question

about fertility was included.

3.5.3.4 Lifestyle factors

This section of the interview included questions about lifestyle factors such as alcohol consumption, smoking, and exercise obtained during and afier pregnancy. Questions about diet, health status, and illicit drug taking during pregnancy were also asked of participants. Final1y, women were questioned about their parmer's smoking habits and extent of alcohol use.

3.5.3.5 Socialsupport

Participants' subjective assessment of the supportiveness of their relationships with family and fkiends at the time of the postpamim interview was ascertained using eight items fiom two instruments: 1) The Social Support Appraisals Scale (SS-A) (Vaux et al., 1986), and 2) The

Inventory of Socially Supportive Behaviors (ISSB) (Barrera et al., 198 1). The SS-A measures the subjective belief that one is loved, respected, and cared for by ftiends, family members, or other individuals. In addition to an overall index of social support, individual subscale scores can be computed for the extent of family support and for fiiend support. The ISSB measures the more concrete or material foms of social support. For instance, such questions assess whether an

individual bas someone she can depend on to watch her children or to provide a place to stay if needed. Carlson and colleagues (1994) used subsets of items from each of these scales (fiend support, family support, instrumental support) and using factor analysis, they confirmed the constnict validity of each subscale. They also demonstrated the intemal consistency (reliability) of the subscales. The coefficients for Chronbach's alpha associated with the Wend, the family, and the instrumental support subscales were 0.88,0.89, and 0.73 respectively.

In the present study, participants were asked to indicate how strongly they agreed with each of the statements on an Cpoint likert scale (1 to 4) ranging flom strongly agree to strongly disagree.

Some items were reversed scored so that higher ratings represented more social support. An overall social support variable was computed by sumrning participants' responses to the questions. Women could receive a total possible scale score ranging from 8 (low social support) to 32 (high social support).

3.5.3.6 History of depression

These self-report questions, which were created for the study, assessed whether participants had a family history of depression, whether they had expenenced any previous episodes of depression including depression afkr a previous pregnancy, and whether during the recent pregnancy they had suffered from depression or had expenenced panic attacks.

3 5.3.7 Postpartum depression (PPD)

The Edinburgh Postnatal Depression Scale (EPDS) (Cox et al., 1987) is a IO-item self-report questionnaire that was used to screen for possible PPD. Participants were asked to rate the frequency with which they bad expenenced each of 10 symptoms within the past 7 days on a 4- point scale (O to 3) ranging hmnever to most of the time. Sorne items were reversed scored so that higher ratings indicated more negative affea. Women could receive a total possible scaie score ranging fiom O (not depressed) to 30 (probably depressed).

3 S.3.8 History of violence

During this section of the interview, women were questioned about their history of emotional, physical, and sexual violence experienced during childhood and during adulthood. Because one of the objectives of the larger study was to conduct a pilot test of the vanous violence instruments, participants received one of two versions of the questionnaires. Version 1 was administered to 104 participants and version 2 was administered to 96 participants.

Emotional abuse was ascertained using questions fiom four instruments: (1) the

Psychological Maltreatment of Women Inventory (PMWI) (Tolman, 1989), (2) the psychological aggression subscale of the revised Conflict Tactics Scales (CTS2) (Straus et al., 1996), (3) the spousal emotional abuse and control questionnaire of the Violence Against Women Survey

(VAWS) (as listed in Johnson, 1996, p. 16I), and (4) the child emotional neglect question included in the National Comorbidity Survey (NCS) (Bromet et al., 1998). Participants who were interviewed during the first part of the study received the PMWI and the NCS (Version 1) while those in the latter part of the study received the VAWS (Version 2). Al1 participants received a question that combined two of the items fiom the psychological aggression scale of the CTS2.

The wording of this new question was "Did your partner shout, yell, insult, or swear at you?".

Participants were asked to respond to tbis question with respect to three different time fiames: 1) in the 2 years prior to the pregnancy, 2) during the pregnancy, and 3) after the birth. Women who responded in the affirmative were further quened as to the number of times that the event occurred during that period of time. Partway through the study, the investigators noted that very few of the participants were endorsing any of the items (i.e., physical, sexual, or injury) within the CTS2 and therefore decided to modiQ the wording of the scaie. Rather than being asked about possible abuse by their 'partner" @= 66), participants were now asked to report abuse that had been perpetrated by "anyone" @= 38). It was thought that the unexpectedly low prevalence rate might have been a consequence of women being explicitly questioned about possible abuse perpetrated by their partner and being uncornfortable to disclose such abuse. At the end of the questionnaire women were then asked to indicate who was responsible for the abuse.

The third instrument used; the VAWS, included five items that probed women about emotionally abusive behaviors and controlling acts perpetrated by their partner.

The final instrument used; the NCS, included one question assessing childhood neglect. A description of the NCS is provided in the section below entitled "Traumatic life events".

Physical violence was assessed using three instruments: (1) the physical assault and injury subscales of the revised Conflict Tactics Scales (CTS2) (Straus et al., 1996), (2) the physical violence questions of the National Comorbidity Survey (NCS) (Bromet et al., 1998), and (3) the

Abuse Assessrnent Screen (AAS) (McFarlane et al., 1992). Participants either received the CTS2 and the NCS (Version 1) or received the AAS (Version 2).

Items fkom both the physical assault scale and the injury scale of the CTS2 were used to assess for possible physical violence. Seven of the 13 physical assault items and four of the six injury items were used. Women were asked to indicate whether they had experienced any of the abusive situations in the 2 years prior to the pregnancy, during the pregnancy, and after the birth.

Because we modified the wording of the items partway through the study, some participants received the questionnaire specifically asking about abuse perpetrated by their "partner" @= 66), while others were asked about abuse perpetrated by "anyone" @= 38).

Four of the five items of the AAS were used to assess physical violence: abuse in the distant pst, abuse in the last 12 months, abuse during pregnancy, and whether the respondent feared her partner or anyone else (McFarlane et al., 1992).

Finally, two physical violence questions were borrowed from the NCS. One question assessed childhood physical abuse and the second question asked whether the participant had ever been seriously physically attacked or assaulted.

Sexual violence was assessed using items from two instruments: (1) the sexual coercion scale of the revised Conflict Tactics Scales (CTS2) (Straus et al., 1996), and (2), Russell's (1986) incest study.

The sexual coercion scale of the CTS2 consisted of seven items, six of which were used in the present study. Participants answered the questions with respect to the three different time frames

(2 years prior to the pregnancy, during the pregnancy, and after the birth), and to either the items refemng to abuse perpetrated by their 'partner*' @= 66) or by "anyone" (n=38).

One question asking about child sexual abuse was rnodified îrom RusselI's incest study

(1986). Respondents who answered in the affirmative were merprobed about the nature of the abuse. Specifically, they were asked when the incident(s) occurred, the duration of the abuse, their relationship with the perpetrator, whether the incident(s) involved attempted or successful intercourse, and whether force was involved.

3.5.3.9 Traumatic life events

During this section of the interview, participants were asked whether they had ever experienced any traumatic life events, such as a nahual disaster, a war, and various types of abusive experiences. Two of the items fiom the original Iist (Bromet et al., 1998), which asked

participants specifically about whether they had been "raped" and "sexually molester, were

replaced by other questions that used behavior-specific wording. The abuse-related traumatic

experiences that were included in this section were used in the calculation of the abuse indices

rather than in the traumatic live events index.

3.5.3.10 Health care utilization

During this section of the interview, participants were questioned about their use of hospital,

prirnary care, and social support services dwing the previous two months. In addition to actual

help seeking behavior, women were also asked if they ever felt that they needed help with a variety of personal, family, or fuiancial problems.

3 -6 Research ethics and participant confidentiality

Ethics approval for this study was received fiom the Hurnan Subjects Review Cornmittee of the University of Toronto (Appendix C), as well as from the Research Ethics Boards of each of the participating hospitals.

To ensure participant confidentiality, each woman who was recruited into the study was assigned a unique identification number, which was written on al1 forms and questionnaires. The list containing participants' names and study numbers was maintained and secured in a cabinet that was accessible only to the investigators and research assistants. The signed consent forms were kept in a separate location fiom both the questionnaires and the subject list. The study number was entered into the electronic database, along with each corresponding woman's data.

Training of interviewers and referral to treatment services Because the interview contained questions that were quite personal and sensitive in nature

(e-g., history of violence, depression, traumatic life events), al1 of the interviewers received

several hours of training prior to being able to conduct any interviews. For ethical reasons this

training was an important part of the study methodology in that these questions could potentially

evoke painful memones and precipitate distressing reactions in the participants who were asked

to reveal traumatic persona1 experiences. Thus, when designing the interview and the training

protocol, the investigators consulted with research experts and clinicians with previous

experience working with such sensitive subject matter. As part of the interviewer preparation, a

list of possible scenarios that might occur during an interview, such as a woman revealing

suicida1 thoughts, becoming agitated or distressed, or disclosing cument abuse, as well as scripted

responses to these scenarios were prepared. If participants became distressed and wanted to

discuss their experiences further, the interviewers made themselves available to listen and to

offer support but did not attempt to council participants.

Al1 of the interviewers practiced conducting the interview with a trained research assistant

who enacted several of these possible scenarios. Following each practice interview, the research

assistant provided the interviewers with feedback regardhg her responses and her manner of

conducting the interview.

A major concem of the investigators was the possibility that a participant might be living with

an abusive man and that her safety might be jeopardized should he learn about the content of the

interview. To address this concem, women were contacted in advance of the interview to arrange

for a convenient time for the interview to take place in private. During the interview, women

were also reminded that they could refuse to answer any questions that were asked of them and that they could end the interview at any time. As part of the ethics review process for each hospital, a referral protocol was arranged for

participants who disclosed a history of recent or past abuse, who had experienced a traumatic life

event, current postpartum stress symptoms, or current postpartum depression. Some hospitals

offered their own services (e.g., St. Joseph's Health Centre had a Women's Health Program that

provided services for women with postpartum depression and a history of violence) and women

who delivered at these hospitals were referred to these specific programs. Altematively, women

were referred to Dr. B. Dorion, Chief Psychiatrist of the Division of Society, Women and Health

at the Clarke Institute of Psychiatry and Women's College Hospital. Women who revealed abuse

were also referred to The Sexual Assault and Domestic Violence Care Centre of Women's

College Hospital.

During the interviews, the interviewers identified women who they believed might need or

benefit fiom referral services. The intenlewer then requested participants' permission for a

member of the clinical referral team to contact them for a consultation. Women who did not feel

comfortable or safe with bis process were given the phone number of a clinician to contact

themselves. Interviewers who were concemed about participants followed up with them on days

and times that were convenient for them and ensured that they were able to arrange for the needed services. 3.7 Statistical method

3.7.1 Database management

Al1 collected data were entered into a Microsoft Access 97 database (Microsofi Corporation,

1997). Field validation rules were programmed into the database to help ensure tùe accuracy of

entered data. These rules specified the range of valid data values that were permissible for each

question. A rule violation, in the form of an out-of range data value, prompted an error message

to be displayed on the screen. Ail entered data were then venfied against the hardcopies of the

questionnaires, and data entry errors were corrected in the database. The Microsoft Access

databases were then imported into SAS (SAS hstitute, Cary NC) for statistical analyses.

3.7.2 Missing data

Participants who bad more than two items missing on the outcome measure were excluded

fiom the bivariate and multivariate analyses. In fact, only two participants each had one missing

item on the outcome rneasure, and thus no one was excluded because of missing data on this

variable. With respect to the predictor variables, missing items on scales with a likert response

format (the Edinburgh Postnatal Depression Scale, the Psychological Maltreatment of Women

Inventory, and the Social Support Scale) were assigned the mean value of the items that were answered by that participant. Respondents who had more than three items missing on any of these instruments were assigned a missing score on the overall variables and were subsequently excluded îrom any analyses that included those particular variables. No respondent was excluded based on these criteria, with the exception of one woman's score on the Edinburgh Postnatal

Depression Scale because she answered the items using an incorrect tirnefiame as the reference period. Respondents who had missing &ta on individual questions that were measured using a dichotomous (i.e., yesho) response format, were assigned a missing score on that variable and were subsequently excluded fiom any analyses that included those particular variables.

3.7.3 Sample size estimation

This study was originally designed as a feasibility study for a larger project aimed at investigating the relationship between a history of violence and postpartum depression, and as such, no formal estimates of sample size were canied out. Because the power of the present study to detect statistically significant associations between the postulated risk factors and postpartum symptoms was unknown, a more liberal statistical criterion was used to determine the variables that would be included in the multivariate logistic regression model. In the bivariate analyses, those predictor variables that were associated with postpartum symptoms at a p < .15 were considered as potential candidates for the model. This more liberal statistical criterion was also used for the stepwise logistic regression modeling, as opposed to the conventional p < .05, so as to help ensure that no important predictor variables were missed.

3.7.4 Definitions of variables

3.7.4.1 Predictor variable definitions

Because this study was exploratory in nature, a number of possible risk factors for postpartum somatic symptoms were evaluated in the analyses. Some of these variables were identified from previous researcb as king known risk factors for either postpartum symptoms or postpartum depression. Other variables were selected because they were clinically meaningful in the context of predicting postpartum somatic symptoms. The predictor variables that were exarnined were classified into three broad categories: psychosocial factors, sociodemographic factors, and health care-related factors, including matemal and obstetrical factors.

3.7.4.1. i Psychosocial predictor variables

Al1 psychosocial variables were ascertained during the postparhim telephone interview and thus were based on participants' subjective self-reports.

3.7.4.1.1.1 History of violence (study objective # 1)

For the analyses, al1 of the violence-related predictor variables were dichotornized; respondents were either classified as abused or as not abused.

T'teetypes of interpersonal violence were exarnined: 1) sexual violence, 2) physical violence, and 3) emotional abuse. These variables were fùrther defined as either having had occurred when the participant was a child or an adult, thereby yielding six variables in total. Childhood violence was defined as abuse that had occurred when the participant was under the age of 14, and violence experienced as an adult was defmed as that having occurred when the participant was greater than 14 years of age. Physical and sexual violence (in adulthood or childhood) and childhood emotional abuse were considered to be present if the participant responded positively to one or more of the items fiom the relevant subscales.

With respect to adult emotional abuse however, because a large proportion of women in our sample reported at least one such incident (60%), a more conservative criterion was used to identifL abused participants. For those who received the first version of the instruments, a respondent was classified as abused if they positively endorsed the emotional abuse question of the CTS or if they indicated 'sometimes', 'often', or 'very oflen' to three or more items from the

PMWI. Participants who received the second version were classified as abused if they had answered yes to at least three of the items on the subscale.

3.7.4.1.1.2 History of depression (study objective #2)

The following four depression-related variables were evaluated: 1) previous episode of

depression, 2) previous episode of postpartum depression, 3) depression during the recent

pregnancy, and 4) family history of depression. These potential risk factors were measwed as

binary variables; respondents were asked whether or not they had been depressed during any of

these time mesand whether they had had a family member who had been treated for

depression.

3.7.4.1.1.3 Other psychosocial predictor variables

in addition to a history of violence and depression, other possible psychosocial risk factors

were evaluated to determine their relationship with postpartum somatic symptoms. These

exposures were fierclassified as having occurred before, during, or after pregnancy.

Before pregnancy Dwing pregnancy Postpartum Traumatic l$ie events, defmed Panic attacks, defined as a Social support, defined as a as a binaq variable. Those binary variable (no versus yes). binary variable. Women were reporting 2 or more of 7 events classified as having low were categorized as high Smoking habits, participants support if they scored between exposure; those reporting O or classified as either non- O and 25, and as having high 1 as low exposure. About 50% smokers or as smokers. support if their score was 26 or of women reported at least one greater. This threshold was event, which was thus a A kohol consumption, deterrnined based on the common experience for this participants classified as either univariate statistics of scale ample of women. non-drinkers or as drinkers. scores; it represents the 75' percentile. lntenàedness of the pregnancy, Exercise, participants classified 7 assessed by two questions as either having exercised or Help with housework, defined asking women whether their not. as a binary variable (no versus pregnancy was planned and Y=). whether it was wanted.

3.7.4.1.2 Sociodemographic predictor variables

Sociodemographic characteristics represent the second set of possible risk factors that were evaluated in the study. Al1 sociodemographic information was collected fiom participants at the time that they were recruitment in the hospital. The following list describes the variables that were analyzed.

Age, defined as a classification variable with three categones (18-29,30-34,35+).

Combined household income, defined as a classification variable with three categories

(<$32,000, $32,000-$80,000, >$80,000).

Highest belof education attuined (of the respondent and her partner), defined as three categories (high school or less, technical or community college, university).

Employment status in theprevious 12 months (of the respondent and her partner), defined as binaiy variables (employed or self-employed, either full-time or part-time venus other).

Born in Canada, defined as a binary variable (no versus yes).

3.7.4.1.3 Health care-related factors, including materna1 and obstetrical factors

The third and final set of possible risk factors for postpartum somatic symptoms included indicators of respondents' pnor health status (pre-pregnancy and antenatally) as well as obsteûical variables related to the labour and delivery. Most of the measures were obtained fiom participants' rnedical records, although a few were assessed dwing the postpartum interviews.

Existing medical conditions with onset prior to pregnancy (obtained fkom medical records),

defined as a binary variable (no conditions versus one or more conditions).

Pariîy (obtained fiom medical records), defined as a binary variable (nulliparous versus

mu1tiparous).

Sick leave duringpregnancy on doctor S orders, defined as a binary variable (no versus yes)

Medical problems duringpregnancy (obtained from medical records), defined as a binary

variable (no problems versus one or more problems).

Length of labour (obtained fkom medical records), defined as a binary variable (less than 12

hours versus 12 hours or more).

Onset of labour (obtained fiom medical records), defined as a classification variable with four

categories (no labour, spontaneous without augmentation, spontaneous with augmentation,

induced).

Mode of delivery (obtained fiom medical records), defined as a classification variable with three categories (spontaneous, assisted vaginal delivery [forceps or vacuum extraction], caesarian section).

Episiofomy(obtained fkom medical records), defined as classification variable with three categories (none, median, medio-lateral).

Length of stay in hospital, defined as a binary variable (2 days or less versus more than 2 days).

Number of maietmal complications, defined as a binary variable (none versus 1 or more).

Type of analgesia/anesthesia (obtained fiom meâical records), defined as a classification variable with three categories (nonemWIV narcotic, regional epidurallspinal, locaVpudendaVgeneral anesthesia). Levef of pain during the labour and delivery, defined as a binary variable (none, very liale, mild versus moderate, severe, very severe ).

3.7.4.2 Outcome variable

3.7.4.2.1 Classification of participants into low and high somatic symptom groups

Most existing studies on women's postpartum health have had the objective of examining the risk factors associated with single health problems such as backache, sexual problems, faecal incontinence and so forth (e-g., Abraham et al., 1990; Brown & Lumley, 1998; Glazener et al.,

1995; Glazener, 1997b; Goldaber et al., 1993; MacArthur et al., 1997; Russell et al., 1996). The present study differed fiom these other investigations in that we were interested in constmcting an outcome measure that represented the severity or fkequency of postpartum symptoms. We opted to dichotomize the variable, as opposed to using the continuous sumrnation due to the positive skewness of the distribution.

In defining such a measure, a variable was first computed that summed the number of symptoms reported by each woman on the postpartum syrnptom checklist. The two breast symptoms were combined to form one symptom because most women who reported having red or tender breasts or mastitis also reported having had sore or cracked nipples. The summation variable was then dichotomized such that participants were categorized into one of two somatic syrnptorn groups. The first group represented a low to moderate symptom group who reported relatively fewer postpartum symptoms and the second group represented those with relatively more symptoms. Because the existing literature provided no guidance as to an appropriate cutoff that could be used to distinguish between these groups, we selected a cutoff based on an examination of the tiequencies and the univariate statistics. We found that at least half of the women in the sample reported experiencing four of the

symptoms on the list: (a) being excessively tired or fatigued (55.0%), (b) backaches (54.5%), (c) breast problems (sore or cracked nipples or red or tender breasts or mastitis) (52.00/0),and (d) difficulty sitthg due to painfiil stitches from the episiotomy or other reasons, or pain fiom the caesarian (49.5%). The next most fiequently reported probiem was hemorrhoids, which was reported by about one-third of our sample (35.5%). The univariate statistics revealed that the mean number of symptoms expenenced was 3.4 (SD = 2.0) and that the 75th percentile was

located at 5.0 symptoms. Based on these figures, we categorized women with five or more symptoms into the high symptom group, and those with four of fewer symptoms into the low symptom group. This threshold provided a sufficient sample size for each of the symptom groups; 140 for the low symptom group and 60 for the high symptom group.

3.7.4.3 Construct validity of the outcome variable

Construct validity refers to the extent to which an instrument measures the concept (Le., construct) that it was designed to measure (Carmines & Zeller, 1979). Construct validation is typically performed when no gold standard or criterion measure (critenon-related validity) exists against which to evaluate the new measure that is being developed (Carmines & Zeller, 1979).

Rather, the process of validating a construct that one wishes to operationalize involves relating the new measure to other theoretically-related measures. Construct validity cm be classified into two subtypes: convergent validity and discriminant validity (Campbell & Fiske, 1959).

Evidence of convergent validity is provided when an ernpincal association between the instrument of interest and other measures of theoretically related concepts can be demonstrated.

Evidence of discriminant validity, on the other hand, is provided when no ernpirical association exists between the instrument and other measures of theoretically unrelated concepts.

Estabiishing the construct validity of a mesure is premised on and strengthened by

demonsbating multiple sources of evidence rather than support for a single prediction (Carmines

& Zeller, 1979).

In the context of the present study, a constmct validation analysis was perfomed in order to

determine whether the women who we categorized into the high symptom group actually

differed nom those in the low symptom group on theoretically relevant measures of physical and

psychological health. This analysis involved comparing the responses of both groups to health-

related questions and scales that were collected during the interview. The first test of convergent

validity was perfomed by comparing the responses of both symptom groups to the self-reported

health status question. If women in the high symptom group were in fact experiencing more

postpartum health symptoms, then one might expect them to have rated their health more

negatively than women in the low symptom group. It was therefore hypothesized that

proportionally more of the high symptom women would endorse the more negative response

options for this question (i.e., poor, fair, or good) compared to low symptom women.

The second test of convergence was a cornparison of the responses of the groups to the question asking whether during the previous 2 months they had ever felt that they needed treatment of a physical problem. It was hypothesized that proportionally more women in the high symptom group would endorse this question relative to those in the low symptom group.

A similar question asking women whether during the previous 2 months they had ever felt that they needed treatment for an emotional or a mental health problem was used to assess the divergent validity of the outcome variable. Although it is plausible that high symptom women might have also been more likely to experience concurrent psychological difficulties for which they might have needed help, it was expected that the magnitude of this association would be

smaller than that for the question asking about treatment of a physical health problem.

The association between these variables and postpartum symptoms was determined using

chisquare tests of association; the continuity adjusted chisquare test was used for two-way tables

and Fisher's exact test was used when more than 25% of the cells had an expected count that was

less than 5.

3.7.5 Measures of effect

3.7.5.1 The prevalence odds ratio versus the prevalence risk ratio

Multiple logistic regression is routinely used in epidemiologic research to test hypotheses about the relationship between postulated risk factors and a dichotomous disease outcorne. A unique feature of this procedure is that it derives estimates of adjusted odds ratios for each of the covariates that are included in the regression model. The odds ratio quantifies the magnitude of the exposure-disease association and is one of the most popular measures of exposure effect fond in epidemiology.

A recent debate bas emerged in the literature regarding the appropriateness of using logistic regression to analyze data that are denved fiom cross-sectional studies (e.g., Hughes, 1995; Lee,

1994; Martuzzi & Elliott, 1998; Nurminen, 1995; Osbom & Cattanizza, 1995; Skov et al., 1998;

Zocchetti et al., 1997). Part of the controversy stems fiom the use of the prevalence odds ratio

(POR, or simply odds ratio (OR)) rather the prevalence proportion ratio ((PRR, or simply nsk ratio (RR)) or the incidence proportion ratio (IPR) as the measure of effect. The PRR and the IPR provide direct estimates of the increased nsk of disease for an individual who bas been exposed to a particular risk factor compared to someone who has not been exposed. These latter two measures are preferred as they provide a direct assessment of excess risk associated with the

exposure, whereas the POR is usually only of interest to the extent that it is able to estimate the

PRR or the IPR. Specifically, when the disease or condition that is under investigation is rare

(i-e., prevalence is less than 10%) the OR generally provides a close approximation of the PRR

(Zocchetti et al., 1997) and the incidence odds ratio of the PR(Greenland, 1987, p. 765).

Cross-sectional studies however, are not efficient means with which to examine rare diseases

as they require large sample sizes to identiS, enough cases to acquire sufficient power to detect

significant associations between the risk factors and the disease (Hughes, 1995). Cross-sectional

designs are typically used to investigate conditions or diseases that are highly prevalent in the

population. In the present study for instance, a large proportion of women reported experiencing

many of the somatic symptoms that were ascertained on the checklist. Furthermore, 30% of

women expenenced the outcome of interest (Le., five or more postparturn symptoms). With

highly prevalent conditions however, the POR generally does not provide an accurate estimate of the PRR. Zocchetti and colleagues (1997) exarnined the relationship between the POR and the

PRR for varying disease prevalence rates and exposure rates. They found that a quaciratic cwe described the association between these effect measures; as disease prevalence increases (e.g., p

= .2, .5, .8) the greater the POR deviates fiom the PRR. Thus, when the prevalence of a condition is -not rare, the POR will always deviate from the nuil and will therefore exaggerate the actual effect of the exposure. The correspondhg confidence intervals for the odds ratio will also be wide, indicating more enor associated with the estimate of the parameter (Nurminen, 1995). In the present study, since the rare disease assumption cannot be satisfied, the prevalence odds ratios derived from the logistic regression cannot be interpreted as an estimate of individual nsk.

As a solution to this problem, some authors have recommended using alternative statistical models that directly estimate the PRR such as Cox's proportional hazards model (Lee, 1994), the log-binomial model (Skov et al., 1998), or directly modeling the propomons rather than the odds

(Zocchetti et al., 1995). Osbom and Cattanizza (1995), on the other hand, have indicated that use of these other models is not necessary and that logistic regression is still appropriate for prevalence studies so long as the investigator is cognizant of these caveats and does not confound the interpretation of the POR with the PRR. They also offer simple conversion fonnulae that allow the investigator to estimate the PRR from the adjusted POR value that is obtained fiom the logistic regression model.

They suggest using Miettenen's test based formula to compute the corresponding confidence intervals. The following expressions were used to calculate the PRR and the confidence intervals:

PRR = (POR)/ { 1+pl(POR- 1 ) ) OR PRR = (POR)( 1+O,)/ ( 1+O ,)(POR))

CI = PRR('*'-~M) (Osbom & Cattamza,l995)

where pl is the prevalence of postpartum symptoms in the non-exposed group, O, is the odds

of postpartum symptoms in the non-exposed group and

z is the square rmt of the chisquare test statistic for the covariate in the regression model

(i.e., the regression coefficient divided by its standard error).

In the present study, multivariate logistic regression was used to examine the independent relationship between the predictor variables of interest and postpartum somatic symptoms (see

Section 3.7.8). The PRR conversion formula was then applied to the adjusted odds ratios to obtain estimates of the magnitude of effeît for the exposure variables. The corresponding confidence intervals were also calculated. Risk ratios that did not encompass the value of 1 were stahstically significant (at p < .05) and were considered to be important predictors of postparhun symptoms. The values of PRR thus provided an estimate of the relative risk of postpartum symptoms that was associated with the predictor variable.

3.7.6 Univariate analysis

The fiequency distributions and the univariate statistics of the predictor variables (individual

items and computed indices) were first examined to determine the following features of the data:

the fiequency of missing responses, the variability (variance, standard deviation, range),

percentiles, measures of central tendency (mean, median, mode), skewness, data outliers, and

nomal probability plots for continuous variables. Variables that performed poorly, because of a

large amount of missing data, a lack of variability in the responses, or low cell numbers were

excluded from the remainder of the analyses.

3.7.7 Bivariate analysis

3.7.7.1 Estimate of unadjusted (crude) odds of postpartum symptoms

Unadjusted relative odds of high postpartum symptoms and 95% confidence intervals were estimated for al1 potential covariates using individual logistic regression models. Dummy variable coding (0, 1) was applied to al1 binary predictor variables; the exposure or risk category of the variables was designated a O and the reference category was designated a 1.

Because the LOGISTIC procedure in SAS treats variables as numeric, (k- 1) dummy variables were defined for classification variables with k (more than 2) levels. For each classification variable, participants were assigned the value O for the dummy variable that represented the category to which they were a member, and were assigned a 1 for the other variables. The reference category (coded as 1) represented the level of the variable that was expected to be associated with the lowest nsk of postparhim symptoms. Durnmy coding was also applied to the outcome variable; the low symptom category (0-4) was designated a 1 and the high symptom

category (5+) was designated a O. Using this coding for the outcome variable, the LOGISTIC

procedure in SAS estimated the odds of having an Uicreased nurnber of symptoms. A unique

featwe of wing durnrny variable coding in logistic regression modeling is that the odds ratio can

be obtained by exponentiating the regression coefficient associated with the predictor variable

(Kieinbaum, 1998). This situation also applies to variables in rnultivariate logistic regression

rnodels that do not include interaction terrns (Kleinbaum, 1998).

Odds ratios that are greater than 1.O0 indicate that the exposure was associated with an

increased odds of postpartum somatic symptoms. Odds ratios that are less than 1.O0 indicate a protective effect of the exposure in that it was associated with a decreased odds of syrnptoms.

3.7.7.2 Testing of predictor variables for the modei

Chisquare tests of association were used to examine the crude association between each of the categorical predictor variables and the binary outcome variable. The continuity adjusted chisquare was used for two-way contingency tables and Fisher's exact test was used when more than 25% of the cells had an expected count of less than 5. Independent sarnples t-tests were used to examine the relationship between continuous predictor variables and the outcome variable.

Continuous variables (e.g., age, length of stay) were also recoded into classification variables, the specific categories king determined by an empirical examination of the frequency distributions.

Chisquare tests were then performed on the new variables. Sorne classification variables that had several response categories (e.g., income, mode of birth) were collapsed into fewer categories to avoid the problem of small ce11 nurnbers in the chisquare and logistic regression analyses. 3.7.8 Multivariable analysis

3.7.8.1 Estimate of adjusted odds of postpartum symptoms

Estimates of the adjusted odds ratios of postpamun symptoms for the predictor variables were

derived using multivariate logistic regression. The advantage of using multivariate modeling

over simple bivariate models is that one is able to determine the independent effect for a variable

(relative odds) by adjus~gfor the effects of the other covariates (Hosmer & Lemeshow, 1989).

To illustrate, when the predictor variables are associated with one another such that the distribution of predictor variable A (e.g., age) differs within the levels of predictor variable B

(e.g., matemal complications), the multivariate estimates the relative odds of having and

increased nurnber of symptoms for matemal complications by 'holding constant' the age variable. Statistical adjustrnent is therefore an important means of obtaining more precise estimates of the association (i.e., relative odds) between the predictor variables and postpartum symptoms.

3.7.8.2 Multicollinearity

Multicollinearity occurs when some of the predictor variables that are included in a multivariable regression mode1 are strongly associated with one another (last, 1988). This situation can produce weliable estimates of the regression coefficients and inflated estimates of the standard errors associated with these parameters (Last, 1988). Before variables were selected for inclusion in the multivariate regression model, the extent of multicollinearity was assesseci by running chisquare tests for each pair of predictor variables. When two variables were strongly associated with one another, the variable that demonstrated the weaker relationship with the outcome variable was excluded. Based on this analysis, one potential covariate was excluded from the model (see Results chapter, section 4.5.4).

The presence of multicollinearity was also evaluated by comparing the estimates of the

regression coefficients and standard enors of the predictor variables in the final logistic

multivariable model with those generated fiom the univariate logistic models that included each

variable on its own. Significantly infiated standard errors for predictor variables in the

multivariable model compared to those provided by the univariate model would provide evidence

of the presence of multicollinearity.

3 J.8.3 Multivariable logistic mode1 building

When screening potential predictor variables for inclusion in a multivariate model, no a prion

rule exists regarding the magnitude of the crude association that should exist between these

variables and the outcorne. Hosmer and Lemeshow (1989) however, recomrnend using a more

liberal statistical criteria (e.g., p c .15) than the conventional p < .05, which might miss

potentially important variables. They indicate that this method is particularly important in

exploratory investigations. Thus, we considered variables to be candidates for inclusion in the

multivariate model if they were significant in the bivariate analysis at a p < .L 5. Because this

study was exploratory in nature, no statistical adjustment was made for multiple compansons.

When developing a multivariate logistic regression model, a number of statistical procedures are available to help identiQ the subset of predictor variables that generate the best fitting model.

The two procedures that were used in the present study were stepwise regression and backward stepwise regression. The significance level entry (for stepwise regression) and significance level stay (for backward elimination) for these models were set at p < .OS.

Stepwise and backward elimination regression procedures do not always produce the same %est fitting model' because they employ different selection des. Therefore, when deciding

which model was best to work with for this analysis, the performance of both models were

compared with respect to model calibration and model discrimination (see section 3.7.8.5). Also,

because these procedures are guided exclusive1y by statistical criteria in the variable selection

process, we also evaluated the clinical meaningfulness and the importance of the selected

variables.

After the base model was generated, we next detemined whether a more parsimonious rnodel could be obtained by tnmming any of the selected predictor variables (Hosmer & Lemeshow,

1989). The importance of each of the variables in the multivariate model was thus detemined by examining the magnitude of the regression coefficients, the odds ratios, and the probabilities that were associated with the partial chisquares.

The decision to trim variables fiom the model was also guided by a concem of avoiding the problem of model overîïtting (Daley & Shwartz, 1997). A model that is overspecified includes too many predictor variables, and although it may generate highly accurate predictions of the outcome in the dataset that was used to develop the model, it may perform poorly if tested on a new sample of individuals. This problem arises because the overspecified model calibrates the data so well that it captures the random emr that is uniquely characteristic of the individuals in the development dataset (Shwartz & Ash, 1997). in addition to demonstrating poor extemal predictive validity, such a model often exaggerates the importance of the selected predictor variables and consequently yields inflated estimates of the regression coefficients and the standard errors (Hosmer & Lemeshow, 1989). In order to avoid the problem of overfitting a model with a binwy outcome variable, it is recommended that the maximum number of predictor variables should be limited to less than 10 percent of the cases that experienced the outcome @aley & Shwartz, 1997). In the present study, because there were 60 women who experienced

five or more postpartum symptoms, the number of predictor variables was limited to five.

To obtain the final mudel and corresponding parameter estimates, the multivariable model was re-run by forcing in the subset of predictor variables.

3.7.8.4 Interaction tenns

When deciding whether or not to include interaction terms in a multivariate model, Hosmer and Lemeshow (1989) recommend using those interactions about which one has pnor reason to be concemed and that make biological sense. This guiding principle is particularly relevant for exploratory studies as the inclusion of a relatively small number of predictor variables in an equation can generate an inordinate number of possible interactions.

In the present study, we had no a prion hypotheses regarding the significance or meanùigfulness of any interactions between the risk factors of interest. Therefore, no interaction terms were considered beyond the assumption in logistic regression of a multiplicative relationship between the covariates included in the model. We did, however, ascertain the statistical importance of adding interaction terms to the final multivariate mode1 by computing the devionce goodness of model fit statistic. Deviance is a likelihood ratio test that is calculated by cornparhg the main effects only model to the sa-ted or "best fitting" model containing these sarne main effects as well as their interaction terms. The saturated model for categorical data contains the same number of parameters as cells and achieves the lowest possible value for the -2LL (and hence the best fit to the data). The difference between the vaiues of the -2LL for the models was then computed.

This difference represents a likelihood ratio test and follows a chisquare distribution with degrees of fieedom qua1 to the difference between the number of parameters in each model. A

statistically significant test (i.e., p < .05) indicates that at least one of the interaction ternis in the

saturated model is significant and that its inclusion in the original main effects only mode1 would

improve the model fit.

3.7.8.5 Mode1 validation

The final multivariate model was evaluated with respect to the following indicators of model

performance: model calibration and model discrimination.

3.7.8.5.1 ModeIcalibration

Measures of mode1 calibration, also called goodness-of-fit, are used to evaluate the accuracy

with which a model predicts the outcome of interest and essentially compare the deviations

between the fitted values and the observed outcome (Hosmer & Lemeshow, 1989). The first

rneasure of calibration that was used in the present study was the Hosmer-Lemeshow chisquare

statistic (H-L).The second rneasure was a likelihood ratio test that compared the minus two log

likelihoods (-2LL)of both models.

The Hosmer-Lemeshow chisquare statistic (H-L) measures the extent of subgroup calibration

for ten groups of individuals fonned by simila.predicted probabilities or risk (Ash & Shwartz,

1997). The average deviation between the predicted values and the observed outcomes within

each subgroup is then calculated and these averages are sumrned to produce the H-Lstatistic.

This test evaluates the nul1 hypothesis that the model is correct and that the predicted

probabilities are in line with observed outcomes. Small values for the statistic, and large associated probabilities @ > .OS) indicate a well-calibrated model.

The likelihood ratio test is computed by taking the difference between the -2LL of two models (or equivalently taking the difference between the deviance scores of both models), and

comparing it to a chisquare distribution with degrees of &dom equal to the difference between

the number of parameters estimated in both models.

3.7.8.5.2 Model discrimination

Model discrimination is a regression diagnostic that represents the ability of a model to

predict higher probabilities of postpartum symptoms, for instance, for those who were

categorized in the high symptom group and lower probabilities for those who were categorized in

the low symptom group (Ash & Shwartz, 1997).

The c-statistic is a rneasure that assesses the discriminatory power of a model. It represents

the area under the receiver operating curve (ROC), which is detemined by plotting the

corresponding proportions of me positives (sensitivities) and false positives (1 -specificity) for

the covariance graph of predicted probabilities for each outcome group (Ash & Shwartz, 1997).

Models with good discrimination will correctly identiQ a large proportion of the cases (high

sensitivity or mie positives) while the proportion of cases that are incorrectly classified will

remain low (few false positives). Thus, a model with perfect discrimination will generate a value of c that is close to 1; a model with no discrimination will generate a value of c that is close to

0.5.

Further evidence of the extent of model discrimination was obtained by exarnining the proportion of observed cases within each of the Hosmer-Lemeshow deciles of predicted nsk.

Models with poor discriminatory power will have the same proportion of cases within each of the deciles whereas models with good discriminatory power will have proportionally more cases located in the upper deciles of predicted risk and fewer cases in the lower deciles. 3.7.8.6 Attributable risk

The attributable nsk (AR), also known as the attributable fiaction, was the second measure of

disease-exposure association used The population AR, also referred to as the etiologic fraction

(EF) provides an estimate of the proportional reduction of the disease that would occur in the

population if an exposure were eliminated. The magnitude of the population AR is determined

not only by the strength of the association between the exposure and the disease (i.e., the

magnitude of the risk ratio), but also by the prevalence of the exposure in the population (Kelsey

et al., 1996). if a strong association exists between the exposure and the disease, but relatively

few individuals in the population are actually exposed to the risk factor, then the AR will be

small (Kelsey et al., 1996). In such a situation, unless the exposure is a necessary condition for

the onset of the disease, only a small proportion of the cases in the population will be attributable

to that exposure. The AR is therefore a usehl measure in public health efforts to identiQ the

important risk factors for a disease and in planning and implementing effective disease

prevention programs (Walter, 1978).

The population AR was calculated as follows:

ARw,,,=p * (PRR- 1)/I +P (PM-1)

. where p is the prevalence of exposure to a specific factor in the study sample . PRR is the adjusted risk ratio (Le., the proportion of high symptom women with the exposure divided by the proportion of high symptom women without the exposure). It was calculated

applying the formula indicated by Osbom and Cattaniua (1995) (see section 3.7.5.1) using the

adjusted odds ratios (from the multivariate model) 4.1 Response rates

Duing the recruitment period of the study a total of 730 women delivered at the six participating hospitals (Centenary Health Centre, 8 1; Women's College Hospital, 1 15; Mount

Sinai Hospital, 14 1; St. Joseph's Health Centre, 15 1; North York General Hospital, 12 1; St.

Michael's Hospital, 121). Afier applying the eligibility critena, 200 of the 730 (27.4%) women were excluded fiom the study: sixty three (8.6%) because they could not conduct the interview in

English, 92 (12.6%) because they either had an infant with congenital anomalies or that required the use of the neonatal intensive care unit, and 45 (6.2%) because they were younger than 18 years of age, had had a multiple birth, would not be reachable for the postpartum interview, or for other reasons. The remaining 530 (72.6%) women met the eligibility cnteria for the study.

There was considerable variability between the hospitals with respect to the proportion of women who met the eligibility criteria: Centenary Health Centre, 67.9%; Women's College Hospital,

79.9%; Mount Sinai Hospital, 75.9%; St. Joseph's Health Centre, 5 1.O%; North York General

Hospital, 83.5%; and St. Michael's Hospital, 8 1.O%. The lower rates for Centenary Health Centre and St. Joseph's Hospital were a result of their having had proportionally more women excluded because of language (1 1.1% and 15.2% respectively) and because of an il1 infant (2 1.O% and

18.5% respectively). St. Joseph's also had 23 (1 5.2%) women who were excluded for the other reasons mentioned above.

The research nurses approached 332 (62.6%) of the 530 eligible women. This number was lower than was anticipated and was a consequence of insufficient research time and resources king available for participant recruitment. This limitation could have had an impact on the 80 representativeness of our sample if women who were approached were systematically different fiom those who were not. In fact, due to our sarnpling method, women who had longer lengths of stay and hence those who had caesarian section delivenes (and related complications) were more likely to have been recruited in the study than those with shorter stays. Although it is unlikely that women who were approached versus not approached systematically differed on other characteristics, this possibility cannot be ruled out entirely.

Of the 332 women who were approached, 253 (76.2%) consented to participate in the study while the remaining 79 (23.8%) women refused participation. The final recmitment response rate, defined as the proportion of wornen who agreed to participate out of the total number of eligible women was 47.7% (253/530).

Postpartum telephone interviews, which were conducted 8 to 10 weeks postpartum, were completed by 200 of the 253 participating women (79.1%). The remaining 53 (20.9%) non- respondents had either changed their minds about participating or were unreachable by telephone

(e-g., the phone number was not in service, incorrect phone number, or unreachable afier eight attempted phone calls).

The overall response rate for the study, defined as the proportion of women who were interviewed (200) out of the total number who were approached (332) was 60.2%. The response rate, when using the number of eligible women (530) as the denominator, was 37.7%.

Of the 200 women who were interviewed, 199 (99.5%) completions were attained. The participant who did not complete the interview had to end the session in order to attend to her infant, and the interviewer was unable to contact her thereafter to complete the interview. The participant did however complete rnost of the interview and her responses were included in al1 analyses that included those variables. Interviews lasted an average of 28.9 minutes (SD = 6.8). The majority of interviews (193200

= 97.5%) were completed in one session, and five interviews (2.5%) required twu sessions.

4.2 Characteristics of the study participants

The sociodemographic characteristics of the respondents @I= 200) are summarized in Table

1. The women ranged in age fiom 19 to 42 years, with a mean age of 3 1.7 years (SD = 5 .O years).

In ternis of their financial status, relatively more women in our sample were located in the upper income categories than in the lower income categones. A combined household income of less than $32,000 per annum (Statistics Canada's 1996 low-income cutoff for a family of four living in Toronto) was reported by 13.4% of the sample compared to 43.3% who reported a combined income of greater than $80,000 per annum. Al1 of the women in the study had a minimum of a high school diploma, and just over half (5 1.5%) of them had attained a university degree. With respect to employment status, 79.5% were employed (either part-time or full-time) in the year prior to the birth, and 12.5% were homemakers. Almost al1 of the women (97.0%) were either manied, in a cornmon law relationship, or had a current paiûier. Finally, just over half (58.0%) of the women indicated that Canada was their country of birth while the remaining 42.0% were quite diverse in their backgrounds.

4.3 Comparison of respondents and non-respondents

To determine the impact of non-response bias on the representativeness of the study sample, respondents and non-respondents (i.e., those who initially consented to participate but who subsequently refused to complete the study or who were unreachable for the interview) were compared on known characteristics. The data for these comparisons were obtained fkom the sociodemographic sweycollected fiom women in the hospital and fiom their medical records.

The results of these cornparisons are presented in Table II.

4.3.1 Sociodemographic characteristics

Respondents and non-respondents did not difTer in age, -t (65.2) = 1.10, p = .28. The mean age of the respondents was 3 1.7 years (- = 5.0) compared to 30.6 years (- = 6.4) for non- respondents. Also, no differences were observed with respect to the level of partner education (xL

(2, -N = 236) = 3.29, p = .19), women's employment status (x2 (1, N = 253) = 1.73, p = .19), or the proportion of women who expected to remto work in the following 6 months (xZ(1, N =

182) = 33, p = .44).

Differences between the two groups, however, were found for the remaining sociodemographic variables. Non-respondents were more than twice as likely than respondents to have reported an income of less than $32,000 in the previous year (3 1.7% versus 13.4%), x2 (2,

-N = 228) = 1 1.89, p = .003. Non-respondents were also twice as likely than respondents to have attained a high school education or less (47.2% versus 24.5%), x2 (2, N = 253) = 13.16, p = ,001.

Non-respondents were more than five times as likely than respondents to have been single, separated, or divorced (1 7.0% versus 3.0 %), x2 (1, N- = 253) = 14.68, p = .O0 1. Finally, non- respondents were more likely to have been bom outside of Canada (62.3% versus 42.0%), x2(1,

-N=253) = 6.13,p= .Ol. 4.3.2 Health care-related factors, including matemal and obstetrical factors

Respondents and non-respondents were also compared on data collected nom their medical records regarding the characteristics of their pregnancy, labour, and delivery. The groups did not differ with respect to par@ (x2(1. -N = 241) = 2.18, e =. 14) or the proportion of women who had had 1 or more medical conditions prior to the pregnancy (x2(1, -N = 239) = 1.27, p = .26). Non-

respondents and respondents were also about equally likely to have had an episiotomy (16.3%

versus 2 1.8%) (x' (2, -N = 237) = 1.49, e = .48) and to have had some degree of perineal trauma

(30.0% versus 40.5%) (x2 (2, -N = 233) = 3.42, p = -18). Finally, no group differences were

observed with respect to the type of analgesia or anesthesia used during labour (x2(2, N = 228) =

2.25, p = .32), medical problems during pregnancy (x2 (1, -N = 239) = 2.90, p = .09), or mode of

delivery (x2 (4, -N = 240) = 8.26, p = .08).

On average, non-respondents had shorter labours than did respondents (5.4 hours versus 8.8

hours), and were less likely to have had a labour that lasted 12 hours or more (13.6% versus

29.8%) (x2(1, -N = 178) = 3.74, p = .OS). Non-respondents were also less likely to have been

induced (12.8% versus 28.0%), x2(1, -N = 233) = 3.85, p = .05. One caveat to the interpretation

of these findings is that because no correction was made for multiple comparisons, it is possible

that these differences may have emerged by chance alone.

4.4 Cornparison of the respondents to the population

The representativeness of the fmal study sample was also ascertained by comparing the

income and education of the respondents to that of the population. Normative data for this analysis were obtained fkom the 1999 General Social Survey (GSS) (Statistics Canada). Using the GSS data, a cornparison dataset was generated that was comprised of women between the ages of 19 and 42 who were residents of Ontario and who lived in an urban center. The results of this analysis revealed that study participants were relatively better off financially and had a higher level of education than did women in the general population. In our study sample, 13.4% of women reported an income of $32,000 or less per annum. This

compares to 2 1.2% of women in the population who reported an income of $29,999 or less.

Income of greater than $80,000 was reported by 43.3% of women in our sample compared to

26.3% of women in the population who reported an incorne of $80,000 or greater.

Respondents were also more likely to have attained a university education than were women

in the general population (5 1.5% versus 26.0%), and about equally likely to have attained high

school or less (24.5% versus 23.1%). Al1 women in the present study had a minimum of a high

school education, whereas 9.3% of women in the population did not graduate fiom high school.

4.5 Statistical analysis

4.5.1 Constnict validity of the outcorne variable

The outcome variable of interest for this study was the fiequency of postparturn health

symptoms. It was defmed as a dichotomous variable; women reporting five or more symptoms

were categorized into the high syrnptom group whereas those with four or fewer symptoms were

categorized into the low symptom group. Because this cutoff was somewhat arbitrary and

because this type of variable had not previously been used or validated in the literature, we

performed a constmct validation analysis to test the relationship between this new variable and

three theoretically-related variables. The extent to which the hypothesized relationships between

these constnicts were supported and actually differentiated participants who were classified as

high symptom (5+) @ = 60) fiom those who were classified as low syrnptom (0-4) @ = 140) would thereby provide some evidence of the validity of the dichotomous outcome variable. Table

UI presents the results obtained fiom the bivariate chisquare tests.

The results of this analysis did provide at lest preliminary evidence for the constmct validity of the outcome variable in httwo out of the three predictions were supported. Convergent validity was assessed by relating the outcome variable to the question asking women whether they had needed treatrnent for a physical problem in the past 2 months. As hypothesized, participants in the high symptom group were significantly more likely than those in the low symptom group to have endorsed this question (47.5% versus 23.6%), (1, -N = 199) = 10.05, p

= .002. Convergent validity was not supported however, on the health status question. It was hypothesized that high symptom women would have rated their health more negatively (Le., as poor, fair, or good) relative to low symptom women. No significant differences were found between the groups, x2 (1, -N = 199) = 1.19, p = .28.

Discriminant validity was assessed by relating the outcome variable to the question asking about help needed in the past 2 months for an emotional or mental health problem. As hypothesized, high and low symptom women were equally likely to have endorsed this question

(1 8.6% versus 1 1.4%), x2(1, -N = 199) = 1.28, p = .26.

4.5.2 Prevalence of postpartum symptorns, history of violence and depression

Tables N and V display the prevalence data for the number of postpartum physical symptoms reported by participants as well as the proportion endorsing each individual symptom in the checklist. The prevalence of the main predictor variables in the study (i.e., history of violence and depression) are presented in Tables VI and VII.

Almost al1 of the women (96.0%) reported experiencing at least one physical syrnptom, and the average number of symptoms was 3.4 (SD = 2.0). The most fiequently cited problems were being excessively tired or fatigued (55.0%), backache (SU%), sore or cracked nipples (49.8%), perineal pain or pain fiom the caesarian (49.5%), and hemorrhoids (35.5%). Approximately one

in four women also reported bowel problems (26.5%) and more heaâaches than usual(23.0%).

4.5.3 Bivariate analysis

4.5.3.1 Estimate of unadjusted (crude) relative odds of postpartum symptoms

The resuIts of the bivariate chi-square tests, the unadjusted relative odds of postpartum

symptoms and 95% confidence intervals for each of the independent variables are dispIayed in

Tables MII-M. Table Vm presents the sociodemographic predictor variables, Table IX presents

the psychosocial predictor variables, Table X presents the healtb care-related predictor variables,

and Table XI presents the violence predictor variables. The odds ratios and 95% confidence

intervals were computed using individual logistic regression models for each covariate. The

definitions for the variables that are included in this list are described earlier in section 3.7.4.1.

Odds ratios that are close to 1 indicate no association between the predictor variable and

postpartum symptoms. Values that exceed 1 indicate an increased risk of symptoms for that

exposure whereas values that are less than 1 indicate a protective effect for that exposure. Based

on the results of the chisquare tests, the factors that were associated with the postpartum

symptoms at a p c .15 were considered as potential candidates for inclusion in the multivariate model.

4.5.3.1.1 Sociodemographic predictor variables (Table VIII)

None of the sociodemographic variables met the cnteria for statistical significance (Le., p c

.15)

4.5.3.1 -2 Psychosocial predictor variables (Table IX)

Three psychosocial variables were associated with postpartum symptoms at p < .15: depression during pregnancy, panic attacks during pregnancy, and help with housework afier the

birth. The relationship between postpartum symptoms and depression dunng pregnancy was in

the expected direction. Participants in the high syrnptom group were more likely than those in the

low syrnptom group to have been depressed during their pregnancy, X' (1, -N = 199) = 7.40, p =

.O 1. Antenatal depression was reported by 28.3% of high symptom women compared to 1 1.5%

of 1ow symptom women (OR- = 3.04; 95% -CI = 1.4 1 - 6.54). The same trend was also found for

panic attacks during pregnancy; high symptorn women were more likely to have reported panic

attacks than were low symptom women (23.3% versus 1 1.5%), ~'(1,N = 199) = 3.70, p = .05.

The relative odds of being in the high symptom group for women with panic attacks compared to

those who did not report panic attacks was 2.34 (95% -CI = 1.O6 - 5.17).

Finally, high symptom women were less likely to have reported not having help with

housework than those who had fewer than five symptoms (16.7% versus 30.0%), x2(1, -N = 200)

= 3.22, p = .07. That is, women with more postpartum health problems were more likely to have

had help with housework. The relative odds of reporting five or more symptoms for those

without help compared to those with help was 0.47 (95% -CI = 0.22 - 1.Ol). This variable was

excluded fiom the final multivariate mode1 as we could not rule out the likely possibility that

having help with housework was a consequence (rather than a predictor) of having more

postpartum health problems.

4.5.3.1.3 Health care-related predictor variables, including materna1 and obstetrical (Table X)

The results of the chisquare tests revealed that five of the health care-related factors were

associated with postpartum physical symptoms: parity, sick leave during pregnancy, mode of delivery, matemal complications, and level of pain during the labour and delivery. High symptom women were more likely to have been nulliparous than were low symptom

women (63.2% versus 47.4%), x2 (1, -N = 190) = 3.38, p = .07. Nulliparity was associated with a

greater odds of reporting five or more symptoms relative to multiparity (- = 1.90; 95% -CI 1.O1

- 3.60).

High symptom women were also significantly more likely than low symptom women to have

taken sick leave during their pregnancy (25.0% versus 10.0%), x2 (1, -N = 200) = 6.46, p = .01.

Sick leave was associated with an increased odds of reporting five or more symptoms relative to

not having taken sick leave (OR = 3.00; 95% -CI = 1.34 - 6.70). Althoügh the duration of leave

reported by women ranged fiom 1 week to 41 weeks, 75% reported a leave of 12 weeks or less

(Median = 8, Mean = 12.3, -SD =I 1.9).

Mode of birth was also associated with postpartum symptoms, X' (2, -N = 190) = 6.35, p = .O4

This association was particularly strong for women who had an assisted vaginal delivery (forceps or vacuum assisted delivery). Among high symptom women, 28.1% had an assisted delivery compared to 15.0% of low symptom women. The relative odds of being in the high symptom group among those who had an assisted delivery compared to those who had a spontaneous delivery was 2.73 (95% -CI = 1.2 1 - 6.14). Furthemore, when the type of assisted delivery was examined in detail, the association was attributable to forceps delivery rather than to vacuum assisted delivery. Comparing high and low syrnptom women, 2 1.O% versus 5.3% respectively had forceps delivery, whereas vacuum assisted deliveries were about equally distributed between the groups (7.0% for high symptom versus 9.7% for low syrnptom women). Finally, the relative odds of having an increased number of symptoms for those who had delivered by caesarian section compared to the spontaneous delivery group was 1.70 (0.82 - 3.53). In ternis of matemal complications, women in the high symptom group were significantly more likely than those in the low symptom group to have had at least one complication (56.7% versus 35.0%), x2 (1,N = 200) = 7.25, p = -01. Matemal complications were associated with an increased odds of reporiing five or more symptoms (oR = 2.43; 95% CI- = 1.3 1 - 4.50).

Finally, women in the high symptom group were more likely than those in the low symptom group to have rated their level of pain during labour and delivery as moderate, severe, or very severe (90.0% versus 77.9%), x2 (1, -N = 200) = 3.34, p = -07. Having had a more painful childbirth was associated with an increased odds of reporting more postpartum physical syrnptoms (- = 2.56; 95% -CI = 1.O 1 - 6.5 1).

4.5.3.1.4 History of violence predictor variables (Table XI)

One violence-related variable was associated with postpartum symptoms: adult emotional abuse. Women who indicated five or more postpartum symptoms were more likely to have reported a history of adult emotional abuse than those who indicated fewer than five symptoms

(40.7% versus 25 .O%), x2(1, -N = 199) = 4.17, p = -04. Women who reported emotional abuse had an odds of reporting five or more postpamim symptoms that was two times greater than women who did not report abuse (95% CI- = 1.O8 - 3.92).

Many studies have documented the CO-occurrenceof emotional abuse and other forms of violence including physical and sexual assault (e.g., Johnson, 1996; Statistics Canada, 2000).

This finding was replicated in the present study as respondents who were identified as having experienced adult emotional abuse were more likely than non-emotionally abused women to have reported a history of adult sexual abuse, child physical abuse, and adult physical abuse (see

Table XII). Thus, the 'adult emotional abuse' vanable, as measured in the present study, captured women with and without a history of other forms of abuse. The question that therefore arises is whether the association that was found between 'adult emotional abuse' and postpartum physical symptoms is a fùnction of emotional abuse specifically (hypothesis A), or to exposure to multiple fotms of abuse among women who reported adult emotional abuse (hypothesis B).

To test hypothesis A, a new variable was created that identified women who were positive for adult emotional abuse but negative for any other foxm of physical or sexual violence. Of the 59 women who reported adult emotional abuse, 33 (33159 = 55.9%) met this new criteria. In this analysis, the remaining 26 women who reported multiple forms of abuse were recoded to missing so as not to confound the 'no abuse' cornparison group. To test hypothesis B, only the 26 (26159

= 44.1 %) women who reported adult emotional abuse and at least one form of physical or sexual violence were positively classified in the emotional abuse group. The remaining 33 women who reported adult emotional abuse alone were recoded to missing. The association between these new 'adult emotional abuse' variables and postpartum physical symptoms was determined using chisquare tests of association.

The results of this analysis, which are displayed in Table XIII, support hypothesis B (i.e., multiple types of abuse). High symptom women were more likely than low symptom women to have reported adult emotional abuse and at least one fotm of physical or sexual violence (25.5% versus 11.8%), x2(1, N- = 166) = 3.8, p = .OS. With respect to hypothesis A (i.e., effect due specificall y to emotional abuse), no statistically signi ficant difference was found between the groups (26.5% versus 16.7%), xZ( 1, -N = 173) = 1.2, p = -27.One caveat that should be noted is that the small sample size in this analysis may have limited our power to detect a significant association. The original 'adult emotional abuse' variable (n=59) was used in the multivariate regression

analysis due to the small sarnple size of the multiple exposure group @ = 26). This original

variable will be referred to hereafter as the 'abuse index' to indicate that for some women it

represents more than adult emotional abuse.

4.5.4 Multicollinearity

The screening process for identivng potential candidate variablesfor the multivariate model

also included an evaluation of the extect of multicollinearity, or the interrelahonship between the

predictor variables. Al1 of the two-way associations between the predictor variables were

evaluated using chisquare tests. Table XIV displays the p-values for these tests; significant

associations (i.e., p 5 -05) are indicated in bold font. When two predictor variables were highly

related to one another, the variable that demonstrated the weakest relationship with the outcome

variable (based on the results of the bivariate chisquare tests displayed in Tables VI11 to XI) was

dropped.

Based on this analysis, one variable was excluded as potential covariate. Level of pain was dropped in favour of mode of birth and matemal complications. Although other predictor variables were statistically associated with each other (e.g., sick leave during pregnancy and depression during pregnancy, x2 (1, -N = 199) = 6.42, E = .O 1, no Merexclusions were made at this point as these variables were not completely redundant with one another.

The final list of predictor variables that were used to build the multivariate model is presented in Table XV. 4.5.5 Muhivariate analysis

4.5.5.1 The muitivariate logistic mode1

In order to determine which of these predictor variables generated the best-fitting multivariable logistic regression model, stepwise and backward elimination procedures were nui using a p < .O5 as the statistical critena for variable selection.

The same three variable model was generated using the stepwise and bacbard elimination procedures: assisted delivery, sick leave during pregnancy, and depression during pregnancy.

This model satisfied the 'rule of 10' which was invoked to avoid the problem of model overfitting, and which limited the number of predictor variables for the present study to five.

4.5.5.2 Mode1 validation

The final multivariate model was denved by forcing in the three selected variables. The indices of model perfomance (i.e., model calibration and model discrimination) for the final model are summarized in Table XVI.

4.5.5.2.1 Model calibration

The results of the Hosmer-Lemeshow goodness of fit test (H-L) revealed that the three- variable model was well-calibrated. The probability associated with the test was -96,which met the statistical cnteria for model fit (Le., p > .05). Because the same model was selected by the stepwise and backward elimination procedures, it was not necessary to calculate the likelihood ratio test to compare the goodness of fit of both models. The three-variable model also demonstrated good performance with respect to the Wald chisquare test for model fit; (xZ=

18.25, p = .OOû4), indicating a significant improvement over the interceptsnly model. 4.5.5.2.2 Mode1 discrimination

Mode1 discrimination provides an assessment of the accuracy with which a model is able to

predict the outcome of interest. Specifically, it evaluates the ability of the model to predict low

postpartum symptoms for those who were actually classified as such, and to predict high

syrnptoms for those who were in the high symptom group. In the present study, model

discrimination was detemined using the c-statistic. A model with good discrimination will yield

a c-statistic that approaches 1, while those with poor discrimination will yield values

approaching 0.5. The discriminatory power of the final three-variable model was a modest .67.

4.5.5.3 Parameter estimates of the best-fitting model

Table XWI presents the parameter estimates for the multivariate and univariate logistic

regression models. The standard emrs and regression coefficients for each of the covariates of

the multivariate model were compared to the corresponding statistics for the univariate models to

ensure that multicollinearity was not a problem. Multicollinearity would have the effect of

generating unreliable and inflated estimates of the regression parameters in the multivariate

model compared to those generated for the univariate models. The estimates derived from the

univariate and multivariate models were, in fact, comparable, indicating that multicollinearity

was not a problem.

4.5.5.4 Interaction terms

The deviance statistic was computed for the final three-variable model as an additional test of goodness of fit. This likelihood ratio test provides an assessment of the statistical improvement in the -2LL of the saturated rnodel that includes interactions over the main-effects only model.

The results of this test were not statistically significant, x2 (3, -N = 189) = 3.41, p = .33. Thus, no significant improvement in the model would be obtained by including any of the interaction

terms between the predictor variables.

4.5.5.5 Estimate of adjusted relative odds and relative risks of postparturn symptoms

Adjusted odds ratios (OR) and 95% confidence intervals were obtained from the multivariable

logistic regression model. Estimates of adjusted relative risks (RR) and 95% confidence intervals

were then calculated from the adjusted odds ratios using the fomulae specified by Osbom and

Cattaruzza (1995) (see section 3.7.5.1). Table XVlTl summarizes these statistics.

According to these data, high symptom women were approximately twice as likely than low

spptom wornen to have had an assisted delivery (RR = 2.04; 95% -CI = 1.26 - 3.29). They were

also about twice as likely (R.J = 2.01) to have been depressed during their pregnancy (95% -CI =

1.20 - 3.38) and 1.92 times more likely to have taken sick leave du~gtheir pregnancy on their

doctor's orders (95% -CI = 1.1 1 - 3.33).

4.5.5.6 Evaluation of depression as a mediatior between abuse and postparturn syrnptoms

As noted in the literature review chapter, one of the mechanisms through which violence is postulated to affect physical health is the psychological sequelae of violence. Depression represents one of the most prevalent psychological responses to interpersonal violence (eg., see

Bohn & Holz, 1996 and Campbell & Lewandowski, 1997 for a review). This association was also confirmed in the present study. Women who reported a history of adult emotional abuse were more likely than women without such a history to have indicaied that they were depressed during their pregnancy, x2(1, -N = 198) = 6.0, p = .O0 1. Thus, if in the present study, antenatal depression functions as such a mediating variable, then including it in the multivariate logistic regression model would have the consequence of underestimating the 'tnie' nsk eflect associated with abuse. It should be stated that because this is a cross-sectional study, the timing of the abuse in relation to the episode of depression was not assessed and is unknown. Therefore, we cannot be certain that the abuse actually preceded the depression.

To determine what would happen to the abuse index when antenatal depression was excluded fiom the multivariate analysis, the backwards stepwise model was re-run by including al1 of the original variables that were used to derive the final three-variable multivariate model (Le., parity, sick leave during pregnancy, matemal complications, c-section, assisted delivery, abuse index, panic attacks during pregnancy). Antenatal depression was excluded as a potential covariate in the model. Again, the significance level stay was set to .05.

The new multivariate model along with the relative odds and 95% confidence intervals are presented in Table XIX. When antenatal depression was removed as a potential covariate, assisted vaginal delivery and sick leave during pregnancy were again independent risk factors, and the abuse index also became statistically significant. The frnal rnodel was derived by forcing in al1 three covariates.

4.5.5.7 Association between postpartum symptoms and postpartum depression

As a final test of the relationship between postpartum physicai symptoms and depression, we determined the association between women's scores on the Edinburgh Postnatal Depression

Scale (EDPS)(Cox et al., 1987) and postpartum physical symptoms. The results of the chisquare tests are displayed in Table XX. There was a positive and marginally significant association between postpartum depression scores and physical symptoms, x2 (2, -N = 199) = 5.79, p = .06.

Women in the high symptom group were more likely than those in the low syrnptom group to

have scored between 9 and 1 1 (1 7.0% versus 7.9%) or 12 and above (1 5.2% versus 9.3%) on the

EPDS. Thus, relatively more women in the high somatic symptom group than those in the low

symptom group were likely experiencing postpartum depression. This finding provides mer

evidence in support of a relationship between postpartum physical symptoms and depression.

4.5.5.8 Attributable Risk

Estimates of the population attributable risk (AR) for assisted delivery, depression during

pregnancy, and sick leave during pregnancy are presented in Table XVIII. These figures indicate

the proportion of high postpartum symptoms in the population that cm be attributed to each of

the risk factors. It suggests the maximum decrease of having an increased number of postpartum symptoms that could occur in the population if each of these factors or 'exposures' were eliminated. In the study, the population AR for assisted vaginal delivery was 16%, that for depression during prepancy was 14%, and that for sick leave during pregnancy was 12%.

Although depression and sick leave may not represent direct causal pathways leading to postpartum physical symptoms, they do suggest that prevention or intervention strategies may be usefùl in mitigating the occurrence of some symptoms.

The RR and population AR were also calculated for the covariates selected by the second logistic regression mode1 (Table XIX). The population AR for these variables were as follows: assisted vaginal delivery (1 6%), the abuse index (1 5%), and sick leave during pregnancy (13%). DISCUSSION

5.1 Summary and interpretation of the fmdings

5.1.1 Postpartum somatic symptorns

The results of this exploratory study lend support to the emerging research literature that has

documented a high degree of matemal health symptoms following childbirth. Ninety-six percent

of women in this study reported at least one health problem in the 2 months following childbirth,

and only 4% reported no problems. The majority of women (62.5%) reported between two and

five syrnptoms.

Other studies that have examined similar postnatal health problerns have reported comparable

figures. Brown and Lumley ( 1998), for instance, found that 94% of their sample of Australian

women reported at least one problem within the first 6 postnatal months while Glazener et al.

(1995) found that approximately 85 to 87% of Scottish women reported at least one problem up to 8 weeks postpartum.

These more 'typical' matemal health outcornes have received relatively little research attention. Consequently, their pervasiveness and the cumulative effect t hat they have on women 's postnatal recovery may not fully appreciated by researchers, clinicians, or even women themselves. Fully half of the women in the study reported excessive tiredness or fatigue, backaches, breast irritation and soreness, and painfui penneum or pain fiom the caesarian wound.

One in three women also reported hemorrhoids, and one in four wornen reported bowel problems and headaches. These symptoms may contribute to a burden of il1 health, and when considered in the broader context of women's lives, they can interfere with women's ability to adjust to new motherhood and to resurne prior work, family, and social roles and responsibilities. 98 Little is known about women's hctional status within these social roles after childbirth, and how their physical recovery may influence the social dimensions of women's lives. One study found that by 6 weeks postpartum, only about half of women (47%) had fùlly assumed responsibilities for infant care, 17% had fùlly resumed household activities, 8% resumed their social and community activities, 27% had fully assumed self-care, and of women who had returned to work, only 18% had attained fùll functional status in this area (McVeigh, 1997).

Physical health-related factors that have been found to affect women's postpartum functional status include level of physical energy (Tulman et al., 1990) and satisfaction with level of stamina and well-being (McVeigh, 1997). Although the extent of physical health symptoms was not considered in these studies, it would be reasonable to expect that expenencing an increased number of negative health expenences after delivery could have a negative impact on postnatal recovery and impede women's ability to assume full fiuictional status within these social roles.

Further research is needed in this area.

Because these postpartwn symptoms may be perceived as only 'to be expected' after childbirth, many women may not seek professional help or treatment for them. Glazener et al.

(1995) reported that between 2 and 8 weeks postpartum, only 18% of women had sought treatment for backaches, 2 1% for tiredness, 27% for urinary incontinence, 33% for headaches,

48% for perineal pain, and 54% for bowel problems. In that study, women cited rnany reasons for not seeking help, including feeling that it was inappropriate to seek help for these problems, feeling that their symptoms were not serious enough, that professional help would not be available or would be ineffective, and that self-help might be more appropriate for addressing their symptoms. 5.1.2 Risk factors for postpartum somatic synptoms

Our study merad& to the body of literature on postparhm matemal health by examining a broader array of nsk factors than has conventionally been studied, including sociodemographic factors, various materna1 or health-cate related factors, and psychosocial factors including a history of violence and depression. Based on the results of the multivariate analysis, the factors that were found to predict an increased risk of high postpartum symptoms were: having had a forceps delivery, having taken sick leave during pregnancy, and having been depressed during pregnancy. A history of adult emotional abuse may also represent a risk factor. However, further research is required to disentangle the influence of abuse versus the psychological sequelae of abuse (e.g., depression) on women's postpartum physical well-being.

5.1.2.1 Forceps delivery

Women having an assisted delivery, and specifically a forceps delivery, reported more physical symptoms in the 2 months following childbirth than did women who had a spontaneous vaginal delivery or a caesarian section delivery. This finding of increased morbidity among women with assisted deliveries has been documented in other studies. Brown and Lumley (1998) found that compared to women with spontaneous vaginal deliveries, those with assisted deliveries were more likely to report perineal pain, sexual problems, urinary incontinence, bowel problems, and hemorrhoids. Similady, Glazener et al. (1995) found that women with assisted deliveries were more likely to report one or more health problems than those with either spontaneous or caesarian section deliveries, and were also more Iikely to report perineal pain, constipation, piles, and stitches breaking down. In the present study, forceps delivery was associated with some of these sarne health problems; narnely perineal pain @ = .02), problems with bladder or incontinence @ = .0002), bowel problems @ = .05), and hernorrhoids @ =

.O00 1)).

Based on a review of the available Merature, Handa et al. (1996) present sorne possible

explanations for the association between forceps delivety and negative physical sequelae. They

reviewed studies that evaluated the effect of childbirth on the pelvic floor and found that relative

to other modes of delivery, forceps delivery was associated with an increased risk of injuries to

this area. During childbirth, pelvic floor trauma in the form of third and fourth-degree lacerations

to the pelvic muscle or to the anal sphincter or damage to the pelvic floor nerves were fond to

increase the risk of urinary incontinence and anal incontinence (Handa et al., 1996). The authors

indicated that it is not yet known whether specific types of forceps (outlet or low forceps) cany

different nsk of injuries. In another study, Abraham et al. (1 990) reported that compared to

women who had an unassisted vaginal delivery, those who had a forceps delivery reported on

average, a longer duration of penneal pain.

5.1.2.2 Sick leave during pregnancy

The second factor that we found to increase a woman's nsk of having five or more postpar&um

health problems was having taken sick leave during pregnancy at the request of a physician. The

reasons that women reported for taking sick leave were quite varied, however, the majonty

indicated reasons relating specifically to physical health problerns or obstetrical problems

associated with their pregnancy. The types of problems included back pain, headaches, pelvic pain, fatigue, cold or pneurnonia, physical work-related conditions, toxemia, nausea and

vorniting, low or high blood pressure, and bleeding. Only one woman who took sick leave reported that it was because of psychological stress. The individual somatic symptoms that were more common among women who took sick leave were: having had more coughs or colds than usual @ = .04) and problems with birth control

@ < .0001). Thus, in this sarnple of women, sick leave most likely represents a measure of antenatal physical health problems or symptoms as opposed to psychological or emotional difficulties during this pend Further support for this supposition is provided by the fact that although sick leave during pregnancy and depression during pregnancy were statistically related to each other (see multicollinearity analysis), these factors were independently associated with the outcome variable in the multivariate analysis. Thus, sick leave taken during pregnancy on the request of a woman's doctor, most likely for physical health reasons, represents another possible marker for postnatal physical health symptoms.

It should also be acknowledged that the relationship between sick leave and postpamirn symptoms might represent a reporting bias in this group of women. Respondents who took sick leave may have simply been more likely to see a doctor during their pregnancy for physical health symptoms and also to report having expenenced postpartum symptoms.

5.1.2.3 Antenatal depression

Finally, antenatal depression represented a clear and strong risk factor for postparturn symptoms. The specific symptoms that were associated with depression during pregnancy were: headaches @ = .03), reliving the baby's birth @ = .004), tiredness or fatigue @ = .04), more coughs or colds than usual @ = .003), and sexual problems @ = .O0 1).

Although the association between non-life threatening somatic symptoms and depression has been well established in the literature, most of these studies have been cross-sectional in nature and most have examined the coexistence of these symptoms at a specific point in time. Few prospective studies have been camed out to determine their temporal relationship and the mechanism by which depression experienced at one point in time may be associated with somatic symptoms at a later time.

Linton (2000) conducted a literature review of prospective studies that evaluated psychosocial factors in back and neck pain specifically, and reported that 13 of 16 studies found that depression represented a risk factor for later pain symptoms. Thus, for these somatic symptoms at least, there does appear to be evidence in support of such a temporal relationship.

Before offering some possible explanations for this relationship, a few study limitations will be noted. First, because this was a cross-sectional study and women were asked to retrospectively recall their level of antenatal depression, it would have been difficult to use objective clinical criteria to measure the extent of depressive symptoms during pregnancy. Participants were therefore asked to indicate subjectively whether or not they were depressed during their pregnancy. Women may therefore have been using different criteria to self-identifi as depressed or not. This of course brings into question the validity of this variable. However, the prevalence of self-reported antenatal depression that we found in the study (16.6%) is in line with the 10% to

16% prevalence figure for major depression during pregnancy that has been cited in the literaîure

(Llewellyn et al., 1997). Furthemore, because it is known that antenatal depression is a strong risk factor for postnatal depression, a Mervalidity check for this question would entai1 finding an association between these variables in the present study. We did in fact find such an association. Women who reported being depressed during their pregnancy were significantly more likely to have scored 12 or above on the Edinburgh Postnatal Depression Scale (24.2% versus 7.9%, p = .01) (EPDS) (Cox et al, 1987), indicating probable postpartum depression.

Another study limitation is that because postpamun symptoms and postpartum depression were marginal1y related (see Table XX), high symptom women wi th concurrent postpartum

depression (and hence negative affect) rnay have simply been more likely to perceive and report

having been depressed dwing their pregnancy.

One likely explanation for the relationship found between antenatal depression and

postpartum physical symptoms is that women who were depressed during their pregnancy were

more likely than non-depressed women to experience an episode of postpartum depression, and

postpartum somatic symptoms rnay have been part and parce1 of the postpartum depressive

syndrome. Several studies have shown that a history of depression, including antenatal

depression, is one of the strongest nsk factors for postpartum depression (Dementein et al.,

1989; Playfair & Gowers, 198 1; Righetti-Veltema et al., 1998; Schaper et al., 1994). In the

present study, we also found a positive relationship between antenatal depression and scores on

the Edinburgh Postnatal Depression Scale (EPDS) (Cox et al, 1987), @ = .O 1).

The reverse explanation is also possible. Women who rnay have been experiencing an

increased number of health problems during their pregnancy, concurrent with mood disturbance,

rnay have been at increased risk for experiencing somatic symptoms afier childbirth. For some

women, many of these health problems (e.g., backache, headache, sexual problems) rnay have

been chronic in nature. Because we did not assess somatic symptoms expenenced during pregnancy, we are unable to distinguish women for whom postpamim health problems were new occurrences fiom women who had ongoing health problems.

These two hypotheses are grounded in the assumption that depression and physical symptoms

CO-existwith one another. The notion that depression alone rnay precede or rnay somehow precipitate non-life threatening somatic symptoms is still equivocal. There is some indication in the literature that this explanation rnay be a less likely scenario. Wagner et al. (2000) tracked a group of primary care patients who were diagnosed at baseline as either depressed (major or minor) or not depressed. They found that depressed patients were typically characterized by persistent physical health problems over tbe year of follow-up, having symptoms that were greater in severity compared to asymptomatic controls. in another prospective study, Von Kofl et al. (1993) failed to find a consistent relationship between depression and subsequent onset of pain symptoms. Thus, more prospective studies are needed to more fully understand if and how depression is associated with new onset physical health problems.

A fourth possible explanation is that depression and physical symptoms may be related to some third factor, an underlying disposition or trait whereby certain individuals rnay be susceptible to a range of negative physical and psychological symptoms (Von KorfT & Simon,

1996). Thus, antenatal depression and postpartum somatic symptoms may have represented specific expressions of this underlying trait, their temporal relationship to each other perhaps being of less importance.

5.1.2.4 Abuse index4

In the first stepwise multivariable mode], the abuse index was found not to be statistically significant. However, there may have been a problem of multicollinearity. Abuse and antenatal depression were significantly associated with one another @ = .008). This relationship is consistent with the literature documenting an increased nsk of depression among individuals with a history of violence. In this study, antenatal depression may have represented a mediating variable between violence and postpartum physical health problems. In such a situation, mediating variables should not be included as covariates in multivariate models as it has the effect of underestimating the 'true' e&t of abuse. We therefore reran the multivariable mode], excluding antenatal depression and found that the abuse index did emerge as statistically significant. Thus, adult emotional abuse represents another possible marker for postpartum physical symptoms. The specific symptoms that were associated with a history of adult emotional abuse were bowel problems @ = .02) and sexual problems @ = .003).

In this study, 'adult emotional abuse' represents a heterogeneous group of women, some of whom also had histories of physical and sexual violence. One of the limitations of the literatwe in terms of our understanding of the health effects of violence is that studies ofien do not consider the independent effects of the various types of abuse. Few studies have taken into account the coexistence of emotional, sexual, and physical abuse or have attempted to systematically disentangle them in the analysis. In the present study we identified women with a history of adult emotional abuse alone, and women with adult emotional abuse and at Ieast one type of physical or sexual violence. We found that the increased risk of postpartum symptoms was probably a function of women having multiple foms of abuse including adult emotional abuse, rather than a function of emotional abuse per se. It should be noted however, that the relatively small sample size in this sub-analysis may have limited our power to detect a significant association. Certainly, the violence literature has documented a positive association between psychological abuse specifically and physical health problems (e.g., Coker et al., 2000 ).

In tenns of explanatory models for the relationship between abuse and physical symptoms, research in this area is sorely lacking. One possible mechanism that bas some face validity in the context of the present study is that abuse may increase the risk of somatic symptoms through the psychological sequelae of violence. Psychological responses to violence may include symptoms such as depression, anxiety, pst-traumatic stress disorder, or other forms of psychological distress (for a review see Campbell & Lewandowski, 1997). Another explanation might be that women within this abuse group who also had histones of sexual or physical might have been at

increased risk of physical symptoms resulting from the violence.

5.2 Methodological issues

5.2.1 Mode of survey administration

The reliability of our survey data may have been affected by our use of a telephone

administered inteniew, as opposed to personal interviews or a self-administered questionnaire.

The different modes of administration have been shown to be associated with certain advantages

and limitations, and the decision to use a specific method is usually determined by a variety of

factors, including time and resources, logistics, the content and the topics examined in the questionnaire, and the characteristics of the study sample (Abramsom & Abramson, 1999).

Self-administered questionnaires tend to be the most cost effective of the three options and can be sent by pst to multiple respondents simultaneously. They have been shown to be better than other interview techniques in eliciting more reporting of pain, disability, emotional disturbance, or other socially undesirable information (see Abranzsorn & Abrarnson, 1999, for a review). This may be due to the anonymity associated with self-completed sweys and with respondents feeling more cornfortable being forthright in their answers or perhaps due to the additional time respondents are afforded to think about the nature of their health experiences.

Thus, postal sweys may have been advantageous in the present study to the extent that we were examining such health expenences as depression, anxiety, and sensitive postpartum problems like birth control, sexual problems, bowel problems, urinary incontinence, and so forth. Thus, it is likely that we had some degree of underreporting of these health expenences.

To evaluate this, we compared the prevalence of some of the more 'sensitive' postpamim physical health problems to that reporteci in the Brown and Lumley study (1998), where a postal

swvey was useds. We found no consistent trend of overreportïng or underreporting in the present

study based on this compatison. Compared to Brown and Lumley (1998), the prevalence of

bowel problems and hemorrhoids was somewhat greater in the present study (bowel: 26.5%

versus 35.5%; hemorrhoids 12.6% versus 24.6%), whereas the prevalence of sexual problems

was lower in our study than in theirs (26.3% versus 6.0%). The prevalence of urinary

incontinence and contraception was generally comparable in both studies.

One of the disadvantages of postal surveys, compared to interview techniques, is that they ofien yield more missing data and lower response rates, potentially resulting in non-response bias among those who may be less literate.

Compared to postal surveys, however, interviews often have better response rates.

Interviewers have better control over respondents' answers and are able to clarify any source of confusion. Interviewers are also able to foster a sense of rapport and an atmosphere of trust with respondents, which are often important when asking questions that are highly personal and sensitive. Feminist research has emphasized that these characteristics are critical in research on violence against women, where the underreporting of violence is the nom (Johnson, 1996;

Acierno et al., 1997). Studies that have used face-to-face interviews with well-trained, sensitive interviewers in a context where women feel safe to disclose her abuse experiences usually produce higher estimates of abuse than do self-administered questionnaires (Ganiararian et al.,

1996).

5.2.2 Other factors influencing the prevalence estimates of violence

It has been difficult to determine precise estimates of the extent of violence against women in society because the figures that have been reported in the literaîure have varied, sometimes quite

dramatically, hmstudy to study. Violence estimates are dependent upon a number of

methodological and conceptual factors. First, the manner in which violence is defined and

operationalized is important. Studies using broader definitions that encompass a wide array of

expenences (e.g., emotional or psychological, physical, sexual assault, sexual harassment)

typically yield higher estimates than studies using a more limited definition or a reliance on a

legal definition of violence (Smith, 1994; Johnson, 1996). Also, important is whether violence is

operationalized as specific acts of abuse or in terrns of women's subjective assessrnent of those

experiences. The tirnefiame used in the study is also relevant; higher estimates will be obtained

when studies measure lifetime prevalence of violence as opposed to violence experienced in the

previous year, for example (Smith, 1994; Johnson, 1996).

The specific wording of the questions will also affwt the reliability of the data. Questions that

use direct, behavior-specific wording describing specific acts of violence are preferable to gateway-type questions that begin by broadly asking respondents whether they had experienced a

"rape" or an "assault" (Acierno et al., 1997). Using multiple measures that ask about abuse experiences in a number of different ways, rather than using a single question, also increases the

likelihood of identibng women who have a history of violence (Smith, 1994). The manner in which the survey is fiamed and introduced is another important issue. For instance, Johnson

(1996) discusses how crime victimization surveys that focus on assessing violent crime have underestimated the extent of sexual assault in women and assault in intimate relationships.

Finally, the charactenstics of the sarnple and the specific sampling firame (e.g., abuse shelters, primary care setting, population or community) will also affect prevalence estimates. 5.3 Strengths and limitations of the snidy

One of the advantages of this study is that women were recruited from six teaching and large

cornmunity hospitals that were located in various regions of Toronto and that served diverse

populations of women. In Ontario, the majority of pregnant women give birth at a hospital. It

was important to survey women fiom a variety of hospitals because some of these hospitals are

known to differ with respect to the characteristics (demographic and clinical) of their patient

populations. For instance, Women's College Hospital specializes in high-risk pregnancies and is

also know to serve women with relatively higher educational attainment and higher

socioeconornic statu. Thus, for the present study, if participants had been recruited fiom only

one hospital or a few hospitals, this could have potentially yielded a study sample that was not

representative of the larger target population of postpartum women. This type of sompling bias

could have compromised the extemal validity (i.e., generalizability) of the study findings

(Fletcher et al., 1982; p. 1 1). That is, it would have only enabled us to extrapolate our findings to

other postpartum women with similar characteristics as those of the study participants rather than to the general population of postpartum women.

One of the study limitations is that our sample was overrepresentated by women who were manied and who had higher incorne and education levels. This unrepresentativeness rnay have been a result of systematic differences between women who continued in the study and wornen who were lost to follow-up. It may also have been a result of recruiting women fiom hospitals such as Women's College and Mount Sinai.

With respect to tbe extemal validity of our findings, we also do not know how women who give birth in small hospitals, nual hospitals, or other non Toronto-area hospitals may have difTered from women in our study sample. Finally, the results of the study may not be generalized to women who were excluded hmthe study (non-English speaking, multiple birth, women with infants who died or who required the use of the neonatal intensive care unit).

Another limitation of the study is that because limited resources were available for participant recruitment, only about two-thirds (62.6%) of eligible women were approached for the study.

This limitation would have had implications for the generalizability of the study findings if there were systematic differences between women who were approached fiom those who were not in terms of any of the variables that were under investigation. This was the case in that women who had longer length of stays were more likely to have been approached than those with shorter stays. Consequently women with caesarian section delivenes (and complications arising fiom these deliveries) were more likely to have been approached as they had longer stays in the hospital post delivery.

A third limitation is that the small cell sizes may have reduced the power of the study to detect statistically significant associations for some of the nsk factors. We did attempt to address this issue to some extent by using a more liberal screening cnteria @ c .15) when selecting candidate variables for the multivariable model. However, some variables that did not meet this statistical cnteria may still be important predictors of women's physical well-being after childbirth. The fact that we did obtain statistically significant associations for some of the risk factors, despite our small sample size however, suggests that the effects for these factors are robust.

Although we exarnined a broad array of possible risk factors, the discriminatory power of the model was modest (c = -67). Other factors that were not considered in the study may be important predictors of postpartum matemal health.

Another methodological issue to be noted is that the questions assessing adult emotional abuse focused on recent abuse or abuse in the current relationship, whereas items assessing adult

physical and sexual violence focused on occurrences at any point during one's life, including

those in the recent and remote past. Regardless of this issue, the small ce11 numbers for sexual and physical violence may have limited our ability to detect significant associations for these

variables. Future studies should attempt to use larger samples to increase the power of the study to fmd a significant effect. It would also bitfiil for future studies to examine the independent effects associated with current or ongoing abuse versus abuse experienced in the past.

Finally, because this study was cross-sectional in nature, two sources of biases may have been present: the temporal sequence of events and old versus new cases (Fletcher et al., 1988). First, with the exception of the sociodemographic survey and the chart review, disease and exposure status were collected simultaneously during the postpartum interview. Thus, for some of the possible 'risk factors' that were examined, it is not possible to confirm that they achially preceded the onset of postpartum somatic symptoms. Second, women who reported postpartum symptoms may have either experienced these symptoms for the first time (incident cases) or may have experienced these problems previously @revalent cases). Thus, it is not possible to interpret a causal association between the identified risk factors and postpamim symptoms.

Although not a study limitation, it should be noted that postpartum somatic symptorns were assessed by asking women to report those symptoms that they perceived as being a 'problem' for them since the birth. Had we asked women to simply report the occurrence of syrnptoms, the prevalence of the various problems could potentially have been greater.

5.4 Implications of the study findings

The findings of this study are important in that they expand upon the growing knowledge base on women's health afier childbirth. A key contribution of the study was in expanding the

definition of women's postpartum health as more than just rare, severe, or life-threatening

problems. This study adopted a population public health approach in which certain health

outcomes are measured and risk factors identified so that appropriate intervention or prevention

strategies may be implemented, thereby reducing the burden of il1 health in women. Considenng

the results of this study in conjunction with the relevant literature, they have implications for

improving pregnancy-related health care offered to women and hopefûlly, in tum, women's

health. It is important to interpret these findings in the context of other research rather than in

isolation because of the potential sources of bias associated with a single observational study

such as this.

A greater awareness of the health outcomes, as well as the four identified risk factors (forceps delivery, antenatal depression, history of adult emotional abuse, sick leave during pregnancy) on the part of prenatal care clinicians could help mitigate the extent to which women experience postpartum physical symptoms. With respect to forceps delivery, the Society of Obstetricians and Gynecologists of Canada have produced clinical practice guidelines outlining safe and appropriate use of forceps during childbirth (1995). Women who take sick leave during pregnancy rnay also represent a group who could be monitored more closely by clinicians during and after pregnancy.

In North Amenca, prenatal care usually involves the routine screening of certain biomedical risk factors in pregnant women. However, psychosocial factors such as depression and violence may be more prevalent than many of the obstetrical factors that are routinely screened in women.

Proper screening, identification, and appropnate prevention and intervention strategies could not only help reduce the potential burden of il1 health in terms of the postpartum health sequelae associa& with these factors, but may also reduce the risk of fùture occurrences of depression

and violence.

Violence itself is cyclical in nature, oflen escalating in severity and fkequency over time and

thus intervening may help break the cycle of violence. There is some evidence to suggest that

violence screening in itself may be a highly effective intervention strategy in reducing future

violence tiom occurring (McFarlane et al., 2000). Professional organizations such as the

American College of Obstetricians and Gynecologists have recornmended the routine screening

of violence by health care providers for al1 patients (1995, 1999). They advocate that screening

take place during the annual medical exam, the preconception appointment, the first prenatal

visit, once per trimester, and during the postnatal checkup. The Society of Obstetricians and

Gpecologists of Canada have also produced a policy statement recommending the routine

screening of abuse and have defined clinical practice guidelines for dealing with violence against

women (1996). Pregnancy and the postpartum period represent times in which otherwise healthy

women corne in regular contact with health professionals for care before, during, and after

pregnancy, as well as for pediatric care. Thus, health professionals are in a unique position to

intervene and assist women in ending violence.

Despite the large body of literature revealing the pemicious health sequelae of violence, general practitioners and obstetricians ofien do not inquire about women's expenences of violence. In the present study, only 8% of women reported ever having been questioned about violence by their doctor and only 1 woman (0.5%) reported being questioned by her obstetrician.

Several barriers to violence screening by physicians have been noted in the literature including fear of offending women, feeling powerless to implement effective intervention strategies, feeling a lack of control over the situation, time constraints, and beliefs that certain women (e.g., the affluent) may not be affected by violence (Sugg & Inui, 1992).

The findings of this study are also important because they confm that physical symptoms

may be more common arnong women with a history of violence and depression than those

without such histories. Thus, women presenting to health professionals with physical symptoms

may represent a manifestation or marker for curent or past depression or violence. This

presentation may facilitate health professionals in identiQing women who might have a history

of violence or depression. Furthemore, addressing women's psychosocial histories, rather than

solely focusing on treating the physical symptoms themselves could improve the overall efficacy

of care provided.

In addition to using the results of studies such as this to inform practicing clinicians, they

could also be incorporated into medical or other educational training programs for pregnancy-

related care. Finally, the results of this and other studies are usehil in that they could be

disseminated to women themselves through clinicians, the popular media, or women's health-

related resources or websites to better inform them about what to expect during the postnatal period as well as the factors associated with postpartum physical well-being.

5.5 Directions for fùture research

This exploratory study exarnined the prevalence of various postpartum health problems in women and identified some of the factors associated with them. Larger-scale prospective studies are needed to more fùlly understand women's health experiences throughout the immediate postnatal period, as well as the longer-term health effects of childbirth. Following wornen over the course of the postpartum year, for example, would provide useful information about the onset, duration, and course of various postnatal health problems as well as the factors that might be associated with persistent problems. Additionally, followuig women during the course of their pregnancy and collecting health, obstetric, psychosocial, or other relevant information would address some of the problems associated with using retrospective, cross-sectional data. It would also allow for baseline Ievels of health symptoms to be assessed and considered in the analyses.

A prospective study in which women are questioned about their history of violence on multiple occasions would also increase the probability of case identification and hence would result in higher prevalence estimates. Over time, women who initially did not disclose their experiences of abuse because of fear, shame, or guilt may feel more cornfortable and safe doing so later on. Also, some women may have forgotten about certain abuse experiences and thus will not report them when first asked, but they may recall them when asked at a later time or afier they have been primed to think about their experiences. Furthemore, a prospective design would provide a better understanding of the timing, pattern, and context in which the violence occurs which would help cl&@ the health impact of violence. It would also enable better intervention and prevention strategies to be developed to stop violence.

It would also be fniitfül for future research to discriminate between women who expenence incident health problems in the postnatal period fiom those who have a history of chronic or recurrent problems. These groups might represent women who expenence a different course of postpartum recovery and in whom specific risk factors rnay be more or less important.

Although we assessed a range of common postparturn symptorns, the list was certainly not exhaustive. Other symptoms that have been documented among postpartum women include anemia, high blood pressure, dizziness or fainting (Glazener, 1997a). Studies with larger sample sizes, and hence more statistical power, would also be able to illuminate the specific nsk factors that are associated with individual somatic symptoms. This analysis was not possible in the ptesent study due to smaH ce11 sizes. FOOTNOTES

1. National lnstitute of Mental Health (NIMH) Epidemiologic Catchment Area Study (ECA)

was a population-based nationwide survey of 18,000 US residents in five communities that

assessed psychiatrie morbidity and health service utilization. Psychiatric morbidity was measured

using the Diagnostic Interview Schedule (DIS), which is a structured interview based on the

cntena delineated in the third edition of the Diagnostic and Statistical Manual of Mental

Disorders (DSM-III; APA, 1980).

2. The Medical Outcomes Study (MOS) was a survey of 1 1,242 outpatients fiom general

practice clinics as well as various medical specialties. It was designed to assess the process and

outcomes of care for specific clinical diagnoses including depression and eight chronic medical

conditions (i.e., hypertension, diabetes, coronary heart disease, angina, arthritis, GI problems,

lung problem, back problems). Depression was assessed using a unique 8-item patient screen,

followed by the administration of the DIS for those who met the criteria for depression on the screen. The medical conditions were assessed by self-report.

3. Small ce11 numbers for some of the symptoms may have reduced the power to detect significant associations. The reported g-values represent the continuity adjusted chisquare test of association or Fisher's exact test. No correction was conducted for multiple comparisons.

4. The abuse index represents a history of adult emotional abuse. However, some women may have also had previous physical or sexual violence.

5. Differences in the prevalence estimates could also have been due to the different time periods used in both studies (8 to 10 weeks in the present study and 6 to 7 months in the Brown and Lumley (1998) study. 118 REFERENCES REFERENCES

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Characteristics of the Study Participants

No (%) of Participants Characteristic @=ZOO)* Age (yeW 19 3 (1.6) 20-24 15 (8.0) 25-29 39 (20.7) 30-34 78 (41.5) 35-39 45 (23.9) 40-42 8 (4.3) (Mean age = 3 1.7years; SD = 5.0) Combined household incorne' -< $2 1,000 > $2 1,000 - $32,000' > $32,000 - 555,000 > $55,000 - $80,000 > $80,000 - S 100,ooo > $100,000 Education Higb school or less Technical or community college Bachelor or undergraduate degree Master's, doctorate, or professional degree 29 (14.5) Employment status in last 12 months Employed (full or part-the) Homemaker Othe$ Marital status Married, common law, part.net 194 (97.0) Single 5 (2.5) Separated, divorced 1 (0.5) Born in Canada No 84 (42.0) Yes 116 (58.0) Table 1 (continued)

No (%) of Participants

Cbarrcteristic @=ZOO) + Country of birth Canada 116 (58.0) Latin America Caribbean Western Europe 10 (5.0) South East Asia 8 (4.0) Eastern Europe 8 (4.0) indian Subcontinent Africa China Middle East United Kingdom United States Other 2 (1.0)

* Questions with missing data will have fewer than 200 respondents + Combined household incorne for 1999 in Canadian currency t Represents Statistics Canada's low-income cutoff for a family of 4 living in Toronto, Canada (1996) : Includes employment insurance or disability benefits, welfare, having been a student or a housewife Table U Cornparison of Respondents and Nonrespondents

No (%) of No (%) of Respondents Non-respondents Characteristic (Nz200) p-53) P valuef Age (Y~W 18-29 30-34 35+ (Mean age) Combined household incorne' < S32,O0Ot $32,000 - $80,000 > $80,000 Education 5 High school Technical or community college University Partner education -< High school Technical or cornmunity college University Employed in last 12 months No: Yes Retum to employment in next 6 month No Yes Marital status Married, common law, pstrtner Single, separated, divorced Born in Canada No Yes Table 11 (contiaued)

Characteristic @=2O@) @=53) P value* Pregnancy and pre-pregaancy Parity Nulliparous Multiparous Existing medical conditionsf1 None 1 or more Medical problems during pregnancyl None 1 or more Labour and delivery Length of labour Less than 12 hrs 12 hrs or more (Mean length of fabor-hours) Onset of labour 0ther8* induced Mode of delivery Spon taneo us Assisted delivery Caesarian section (emergency) Caesarian section (elective) Caesarian section (emergency/elective unknown) Episiotomy None Median Medio- lateral Table II (continued)

No (%) of No (%) of Respondents Non-respondents @=2OO) (Nt531 P value* - -- - Perineal Trauma None 109 (59.6) 35 (70.0) -18 la - 2"6degree 68 (37.2) 12 (24.0) 3d - 4& degree 6 (3.3) 3 (6.0) Type of analgesia or anesthesia None, IM/IV narcotic Local, pudendal, general anesthesia 21 (11.3) 9 (19.6) Regional epidwal or spinal 148 (79.6) 33 (71.7)

* pvalue for the chisquare test; continuity adjusted chisquare for 2*2 tables or Fisher's exact test + Combined household income for 1999 in Canadian currency t Represents Statistics Canada's low-income cutoff for a family of 4 living in Toronto, Canada (1996) $ Includes employment insurance or disability benefits, welfare, having been a student or a housewife p-value for the independent samples t-test assurning unequal variances I( Includes such conditions as allergies, asthma, heart disease or circulatory disease, arthritis, high blood pressure, thyroid problems, depression, systemic lupus, and multiple sclerosis 7 Includes such problems as essential hypertension, pre-eclarnpsia or toxemia, antepartum bleeding, intrautenne growth retardation, infections, and anaemia ** Includes spontaneous labour without augmentation, spontaneous labour with augmentation, and no labour III p-value for the independent samples t-test assurning equal variances Table ïïï Construct Vliüdity of the Outcome Variable

No (%) No (%) 0-4 symptoms 2 5 symptoms Variable @=140) (Ne) P value* In the past two months, was there a time when you felt you needed treatment of a physical problem No Yes In the past two months, was there a time when you felt you needed heip with an emotional or mental health problem No Yes Health status Pwr, fair, good Very good, excellent

* p-value for the chisquare test Table IV Number of Postpartum Somatic Symptoms

No (O/.) of Parücipanis Number of Somatic Symptoms @=200) Cumulative Percent O 8 (4.0) (4.0) 1 29 (14.5) (18.5) 2 38 (19.0) (37.5) 3 35 (17.5) (55.0) 4 30 (15.0) (70.0) 5 22 (11.0) (8 1 .O) 6 26 (13.0) (94.0) 7 6 (3.0) (97.0) 8 3 (1.5) (98.5) 9 3 (1.5) (iOO.0) Table V Prevdence of Postpartum Somatic Symptoms

No (%) of Participants Somatic Symptom @=2W Excessively tidor fatigued 110 (55.0) Backac hes 109 (54.5) At lest one breast symptom (sore or cracked nipplcs, red or tender breasts or mastitis) Sore or cracked nipples Perineal pain or pain from the caesarian Hemorrhoids Bowel problems Bad headaches 46 (23.0) B ladder pro b lems Red or tender breasts or mastitis More coughs or col& than usual 14 (7.0) Sexual problems Roblems with birtb control Constantly reliving the baby's birth Table VI Prevalence of a History of Violence

No (96) of Participants Type of Violence @=200) Childhood sexual abuse 28 (14.1) Adult sexual abuse 26 (13.0) Any sexual abuse 47 (23.5)

Childhood physical abuse Adult physical abuse Any physical abuse

Child emotional abuse Adult emotional abuse Any emotional abuse

Any abuse 86 (43.4) Table VI1 Prevalence of a Aistory of Depression

No (%.) of Participants History of Depression (N-W Depression prior to pregnancy 45 (22.7) Depression afler a previous pregnancy (among those 30 (30.3) who had a previous pregnancy) Depression during this pregnancy 33 (16.6) Any close relatives treated for depression 32 (16.3) Table VIII Bivariate Analysis Chisquare Tests and Unadjusted Relative Odds of Postpartum Somatic Symptoms Sociodemographic Predictor Variables

No (94) No (a/.) 0-4 symptoms 2 5 symptoms Characteristic (N440) (N4) P value* OR 95 % CI Age (years) 19-29'' 30-34 35-42 (Mean age) Combined household income'

== $32,000' S32.000 - $80,000 > S80,000R Education High school or less Technical or community college Universi@ Partner education High school or less Technical or community college UniversityR Employed in last 12 rnonths NO^ YesR Born in Canada No YesR

E-value for the chisquare test; continuity adjusted chisquare for î52 tables or Fisher's exact test Reference category Combined household income for 1999 in Canadian currency Represents Statistics Canada's low-income cutoff for a farnily of 4 living in Toronto, Canada (1996) Includes employment insurance or disability benefits, welfare, having ken a student or a housewife E-value for the independent sarnples t-test assurning equal variances Table IX Bivariate Analysis Chisquare Tests and Unadjusted Relative Odds of Postpartum Somatic Symptoms Psycbosocial Predictor Variables

------No (%) No (%) 0-4 symptoms 2 5 symptoms Variable (N=140) @=60) P value* OR 95 % CI Before pregnancy Previous personal history of depression NoR Yes Depression after a previous pregnancy NoR Yes Close relatives treated for depression NoR Yes Traumatic life events 0-1 evenP 2+ events Pregnancy planned No YesR During pregnancy Srnoked during pregnancy NoR Yes Alcohol consumption during pregnancy NoR Yes Exercise during pregnancy No YesR Table IX (continuai)

No (%) No (74) 0-4 symptoms 2 5 symptoms Variable QI-1 40) @-6û) P value* OR 95 74 CI Depression during pregnancy NoR 123 (88.5) 43 (71.7) .O 1 1 .O0 Yes 16 (11.5) 17 (28.3) 3.O4 Panic attacks during pregnancy NoR 123 (88.5) 46 (76.7) .O5 1 .O0 Yes 16 (11.5) 14 (23.3) 2.34 Postpartum Help with housework No 42 (30.0) 10 (16.7) .O7 0.47 YesR 98 (70.0) 50 (83.3) 1 .O0 Social support Low 39 (27.9) 17 (28.3) 1 .O0 1 .O2

* p-value for the chisquare test; continuity adjusted chisquare for 2*2 tables or Fisher's exact test R Reference category Table X Bivariate Analysis Chisquare Tests and Unadjusted Relative Odds of Postpartum Somatic Symptoms Health CareRelated Factors, Including Materna1 and Obstetrical Predictor Variables

04symptoms 5 symptoms Variable (N=140) (N-60) P value* OR 95 % CI Before pregnancy Existing medical conditions' NoneR 1 or more During pregnancy Parity Nulliparous MultiparousR Sick leave on doctor's orders NoR 126 (90.0) 45 (75.0) .O 1 1.O0 Yes 14 (10.0) 15 (25.0) 3.00 (1.34 - 6.70) Hospital admission during pregnancy NoR 128 (91.4) 51 (85.0) .27 1.O0 Yes 12 (8.6) 9 (15.0) 1.88 (0.75 - 4.74) Medical problems during pregnancyt NoneR 97 (73.5) 37 (66.1) .39 1.00 1 or more 35 (26.5) 19 (33.9) 1.42 (0.72 - 2.79) Labour and delivery Length of labour Less than 12 hrsR 64 (70.3) 30 (69.8) 1.O0 1.O0 12 hrs or more 27 (29.7) 13 (30.2) 1.03 (0.47 - 2.27) (Mean fength of labor-hours) 8.2 10.0 -15s Onset of labour Othe$ Induced Mode of delivery SpontaneousR Assisted delivery Caesarian section Table X (continued)

No (%) No (%) 04symptoms 2 5 symptoms Variable (N+W @=6û) P value* OR 95 ./. CI Episiotomy NoneR 105 (80.2) 42 (73.7) 0.16 1.00 Median 17 (13.0) 6 (10.5) 0.88 (0.33 - 2.39) Medio-lateral 9 (6.9) 9 (15.8) 2.50 (0.93 - 6.73) Length of stay in hospital 2 days or lessR 82 (58.6) 30 (50.0) .34 1.00 More than 2 days 58 (41.4) 30 (50.0) 1.4 1 (0.77 - 2.60) (Mean length ofstay-days) 2.5 2.7 .45O Number of maternal complications NoneR 91 (65.0) 26 (43.3) .O 1 1.O0 1 or more 49 (35.0) 34 (56.7) 2.43 (1.3 1 - 4.50) Perineal Trauma NoneR 1" - 2"6 degree 3d - 4* degree Type of analgesia or anesthesia None, IM/IV narcoticR 14 (10.7) 3 (5.4) .40 1.O0 Local, pudendal, general anesthesia 16 (12.2) 5 (9.1) 1.46 (0.29 - 7.23) Regional epidural or spinal 101 (77.1) 47 (85.4) 2.17 (0.60 - 7.92) Leve! of pain None, very little, mildR 31 (22.1) 6 (10.0) .O7 1.O0 Moderate, severe, very severe 109 (77.9) 54 (90.0) 2.56 (1.0 1 - 6.5 1)

* p-value for the chisquare test; continuity adjusted chisquare for 2*2 tables or Fisher's exact test R Reference category + Includes such conditions as allergies, asthma, heart disease or circulatoty disease, arthritis, hi@ blood pressure, thyroid problems, systemic lupus, and muttiple sclerosis t Includes such problems as essential hypertension, pre-eclampsia or toxernia, antepartum bleeding, intrauterine growth retardation, infections, and anaemia includes spontaneous labour without augmentation, spontaneous labour with augmentation, and no labour $ pvalue for the independent samples t-test assuming equal variances Table XI Bivariate Analysis Chisquare Tests and Unadjusted Relative Odds of Postpartum Somatic Symptoms History of Violence Predictor Variables

No (%) No (%) û-4 symptoms S symptoms Type of Violence @=140) (Ne) P value* OR 95 '!!hCI Childhood sexual abuse NoR Yes Adult sexual abuse NoR Yes

Childhood physical abuse NoR Yes Adult physical abuse NoR Yes

Child ernotional abuse NoR Yes Adult ernotional abuse NoR Yes

e-value for the chisquare test; continuity adjusted chisquare for 2*2 tables or Fisher's exact test R Reference category + Includes abuse experienced as a chilci, or as an adult, or both t Includes sexual, physical and emotional abuse Table XII Relitionsbip between Adult Emotional Abuse+ and Other Physical and Sexual Abuse Types

No adult emotional abuse Adult emotional abuse Type of Violence @I=140) @=59) P value* Childhood ;ex& abuse

Adult sexual abuse No Yes

Childhood physical abuse No Yes Adult physical abuse No Yes

* pvalue for the chisquare test; continuity adjusted chisquare for 2.2 tables or Fisher's exact test + Respondents teporting adult emotional abuse with or without a history of physical or sexual violence Table XLII Relationship between the New Adult Emotionrrl Abuse Variables and Postpartum Somatic Symptoms

Type of Violence 0-4 symptoms 2 5 symptoms P value* Adult emotional abuse only (no history of physical or sexual violence)

Yes

Adult emotional abuse and at least one fonn of physical or sexuaI violence No 105 (88.2) 35 (74.5) .O5 Yes 14 (11.8) 12 (25.5)

p-value for the chisquare test Table XW Multicollinearity Analysis*

. Depr dunng Panic anacks Parity Sick lave Mode of LeveI of Matemal Variable pregnancy during during binh pain compfications pregnancy PregnanCY Panic attacks during pregnancy .O6

Sick lave during pregnancy .O1 .78 1.00

Mode of birth .16 .61 .O01 .25

Level of pain -76 -12 1 .O0 1 .O0 ~.OOO1

Materna1 complications .O6 -10 .68 .32 .25 .O3

Abuse index+ .O1 .O3 .33 .O3 .OS .54 -7 1

* p-value for the chisquare test; continuity adjusted chisquare for 2*2 tables or Fisher's exact test + Adult emotional abuse; includes women with and without previous physical or sexual violence Table XV List of Predictor Variables for the Multivanate Logistic Regression Model*

Variables

Sociodemographic predictor variables N/A

Psychosocial predictor variables Depression during pregnancy Panic attacks during pregnancy

History of violence predictor variables Abuse index'

Herltb care-related predictor variables Parity Mode of delivery (assisted delivery) Mode of delivery (caesarian section) Sick lave during pregnancy Materna1 complications

* This list includes al1 variables that were associated with postpartum somatic symptoms (p < .15) in the bivariate chisquare analysis + Adult emotional abuse; includes wornen with and without a history of physical or sexual violence Table XVI Mulîivariate Analysb: Regression ~ia~nostics*

Model Performance Staüstics

c-statistic -2LL -2LL Wald x2+ P value' H-L: (intercept only) (intercept rad covariates)

Although there were 200 respondents in the study, not al1 individuals had data on al1 of the covariates that were included in the multivariate model. Those with missing data on at least one of the covariates were excluded fiom the model. The final sample size for the model was 189. Wald chisquare test for the model p-value for the Wald chisquare test for the model pvalue for the Hosmer-Lemeshow chisquare test for gooàness of model fit Table XVII Multivariate Andysis Parameter Estimates from the Univariate and Multivariate Logistic Regression Models

Univariste Modeisf Multivariate Model - p+ SE' Pz OR' Pt SE' Px ORif Variable Assisted deiivery** 0.79 38 .O4 2.20 1.18 0.41 .O04 3.26 Depression during pregnancy 1.11 .39 -004 3.04 1.14 0.43 -008 3.11 Sick leave during pregnancy 1.10 .41 -007 3.00 1 .O5 0.45 .O2 2.86

Individual logistic regression models for each predictor variable, with postpartum somatic symptoms as the outcome variable. + Regression coefficient (beta) associated with each of the predictor variables. For the univariate models, these estimates are the unadjusted coefficients. For the multivariate model, these estimates are the adjusted regression coemcients after 'forcing in' the variables. t Standard error associated with the estimated regression coefficient $ Probability associated with the partial (Wald) chisquare test statistic for the predictor variable § Estimate of the unadjusted relative odds of high postpartum symptoms 1 Estimate of the adjusted relative odds of high postparturn symptoms ** Spontaneous delivery and caesarian section delivery were combined to form the reference category Table XVLII Relative Odds and Relative Risks of Postpartum Somatic Symptoms

Unadjusted Adjusted Variable OR 95 ./.CI OR 95%CI RR 95 ./.CI A& Mode of delivery

Caesarian sectionR 1.O0 1.O0 1.O0 Assisted delivery 2.20 (1.04 - 4.66) 3.26 (1.46- 7.26) 2.04 (1.26 - 3.29) 16% Depression during pregnancy NoR 1.O0 1 .O0 1.O0 Yes 3.04 (1.41-6.54) 3.11 (1.34-7.23) 2.01 (1.20-3.38) 14% Sick leave during pregnancy NoR 1.O0 1.O0 1 .O0 Yes 3.00 (1.34 - 6.70) 2.86 (1.18 - 6.96) 1.92 (1.1 1 - 3.33) 12%

R Reference category Table XIX Relative Odds of Postpartum Somatic Symptoms Muitivariate Mode1 Derived Excluding Antenatal Depression as a Potentiril Covariate*

Unadjusted Adjusted Variable OR 95%CI OR 95%CI RR 95%CI A& Mode of delivery SpontaneousR 1 .O0 1 .O0 1 .O0 Caesarian sectionR 2.20 (1.04 - 4.66) 1.00 1 .O0 Assisted delivery 1-00 3.15 (1 -42- 7.02) 2.00 ( 1.23 - 3.25) 16% Abuse index NoR Yes Sick leave during pregnancy NoR 1.O0 1 .O0 1 .O0 Yes 3.00 (1-34 - 6.70) 3.33 ( 1 -40 - 7.94) 2.06 ( 1.22 - 3.48) 13%

* This mode1 was derived using both forward and backward stepwise logistic regression + The confidence interval encompasses 1 because this final model, which had angof 189, was derived by forcing in the three covariates that were selected by the backward elimination procedure. In this final model, the p-value for the abuse index was .07. When the original backward elimination was run, the N for that mode1 was 188 and the pvalue for the abuse index was .OS. R ~efzncecategory Table XX Relationship between Postpartum Depression and Postpartum Somatic Symptoms

- No (%) No (54) 0-4 symptoms 15symptoms Variable @ 440) @=a) P valuef Scores on the Edinburgh Postnatal Depression Scale (EPDS)

Scores on the Edinburgh Postnatal Depression Scale (EPDS) 127 (90.7) 50 (84.8) -33 0-1 1 13 (9.3) 9 (15.2) 12+

* p-value for the chisquare test; continuity adjusted chisquare for ZL2 tables APPENDICES Appendix A

Information Package for Potential Participants (insert hospital logo)

About the LEAP study ...

Wbat is it? The Life Events after Pregnancy (LEAP) pilot project is a research study taking place in this hospital and five others in Toronto. The project is being conducted by the Centre for Research in Women's Health, the University of Toronto and (insert hospitul S name). The purpose of the study is to learn more about the health of women after pregnancy. Our study will try to find out about two main issues: first what are the stresses, strains and feelings that women experience afier birth; and second how does a woman's physical and mental health and her close persona1 relationships during pregnancy affect her feelings and health after birth. We also want to know what kinds of support women have at home and more about their family and personal relationships. This will enable us to plan better programs for women in the future.

Who are the researchers? From the University of Toronto: Principal Investigator-Marsha M. Cohen MD, Professor Co-investigators : Bent Shei MD, Andrew Willan PhD, Ruth Gallop Pm,Donna Stewart MD From (ïnsert hospital S name): (insert name of huspitul representative hospital)

Who are the potential participants? We are inviting women like yourself who have just given birth to a new baby to participate in the study.

What does the study involve?

Short interview At the hospital, we will interview each woman who agrees to participate. We will ask a few questions about her background, education, income and employment.

Chart review We will review the medical records related to your pregnancy, labour and birth in hospital. This will allow us to improve the study by adding information on your physical health during pregnancy and if there were any problems you may have had during the birth.

Telephone interview A research assistant will cal1 in 8 to 10 weeks time. She will first cal1 to set up a time that would be best for you when can talk in pnvate. During the interview we will ask questions about your physical and mental health during and after pregnancy including issues around your pregnancy, labour and delivery, and infant feeding. We will also ask about your experiences on a number of personal issues for women such as what kind of support you have at home, your relationship with your family and partner, how you resolve conflicts between you and your partner, if you have had accidents and injuries in the past, and what are your feelings and stresses after birth. This interview will take approximately 25 to 35 minutes of your time and will involve a number of different types of questions, some of which may be of a sensitive nature.

Are there potential harms and benefits from being involved in the study? Although you and your farnily will not benefit directly from the study, the infomation gained may benefit other women in similar circumstances in the future.

There are generally no risks to a woman when answering questionnaires. There may be a srnall chance that some questions of a personal nature may cause a strong emotional reaction in a few women. If this should happen, our research assistant will be able to direct you to someone who can help you if you should need this. However, you can withdraw fiom the study at any time or refuse to answer any specific questions. Even your help with answering some of the questions will be valuable to the study.

Confidentiaüty Please be assured that al1 the information you provide or that fiom your medical records will be kept strictly confidentid and that your responses cannot be identified individudly. An identification number is written on the fiom sheet of your interview questionnaire so that only we know who has completed the interview and so that we can contact you for fiinire interviews. However, the kom sheet will be removed from the questionnaire and no identimng information (including narnes, dates or addresses) will be used after the interview is completed. The fiont sheets and the questionnaires will be kept in locked cabinets and only the research staff will have access to them. Al1 questionnaires will be destroyed once the study has been completed. Any reports or publications arising fiom this study will use group information only so that no one person can be identified in any way.

Participation ts voluntary Your participation is totally voluntary. If you choose not to participate this will not have any effect on your health care provision by your doctor or your hospital. As noted above, if you choose to participate, you cm withdraw fiom the study at any time or refuse to answer any speci fic questions.

Need more information or have questions? Please let us know if you have any questions about any aspect of this study or if you would like more information. You may contact our research coordinator: Lynda Sellar at (4 16) 3 5 1-3 800 ext.2723; fax 35 1-3 746 or e-mail: [email protected]. This study has been approved by Research Ethics Board of the University of Toronto. If you have any question about the rights of research study participants, please contact Nomi Rotbard, the Research Ethics Board Co-ordinator at the Center for Research in Women's Health at (416) 35 1-3733. Appendir B

Consent Form

Appeodir C

Ethics Approval University of Toronto

OFFICE OF RESEARCH SERVICES

PROTOCOL REFERENCE M26 t

Dr. MICohen Centre for Research in Wornen's Health 790 Bay Streeq Ste. 75 1 Toronto, ON M5G IN8

Dear Dr. Cohen:

Re: "(1) Life events afier pregnancy (LEM) and (2) Life events after pregancy (LEM) pilot" by Dr. M. Cohen

Weare writing to advise you that a Review Cornmittee composed of Drs. J. Barnsley, T. Meyrs, E. Hodnett and L. Yuen has =ganteci approval to the above-named resevch sîudy.

The approved revised consent form (jan. 7, 1999) is attached. Subjects should receive a copy of theu consent form.

During the course of the research, any sigdicant deviations aom the approved prorocol (that k, any denation which would lead to an increase in risk or a decrease in benefit to haman subjects) andor any unanticipated developments within the research should be brought to the attention of the Office of Research Senrices.

Best wishes for the successful completion of your project.

Yours sincercly,

Executive Officer Human Subjects Review Cornmittee

SP/mr Enclosures Cc: Dr. P. Leatt

Simcoe Hall ZKinges Co~cgeCircie Tomnto Ontrrio %ES Ml Teiephone .Z'Lé/ 973-a63 Fax a&/971-20i0